Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: a retrospective observational study

Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: a retrospective observational study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: a retrospective observational study Tomohiro Mitoma, Shujiro Sakata, Ayano Suemori, Hikaru Ooba, Kei Hayata, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6938564/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background To assess the utility of intraoperative transvaginal ultrasonography (TVUS) in evaluating the duration of blood flow in cervical varicosities as a real-time diagnostic marker for placenta accreta spectrum (PAS) in placenta praevia. Methods This single-centre historical cohort study included patients with placenta praevia who underwent caesarean section with intraoperative TVUS. The primary outcome was blood flow persistence time, defined as the interval from fetal delivery to disappearance of low-velocity (≤ 2.0 cm/s) colour Doppler signals in cervical varicosities—dilated venous structures in the cervical stroma commonly observed in abnormal placentation. TVUS was performed in the sagittal plane including the internal cervical os. Flow persistence time was retrospectively measured from surgical video recordings and was independently assessed by two obstetricians. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of flow persistence time for predicting PAS. The area under ROC curve (AUC) was calculated to assess discriminative ability. Optimal cutoff values were determined using sensitivity, specificity, and predictive values. Multivariate regression identified independent predictors of PAS, and model performance was evaluated using AUC. Results Among the 52 included cases, PAS was diagnosed in 20 (38.5%). Blood flow persistence time was longer in PAS cases (20.20 ± 14.31 min) than in non-PAS cases (5.69 ± 2.46 min). A cutoff of 7 min yielded a sensitivity of 1.00 and specificity of 0.72 for PAS diagnosis (AUC = 0.94), reliably ruling out PAS when flow ceased within this time. Conversely, a duration of ≥14 min had a positive predictive value of 1.00, strongly indicating the presence of PAS. Multivariable analysis confirmed that flow duration was an independent predictor of PAS (AUC = 0.95). For predicting hysterectomy, a threshold of ≥14 min achieved a specificity of 0.96 and a negative predictive value of 1.00. Conclusions Intraoperative measurement of cervical varicosity blood flow duration via TVUS offers a reproducible, real-time physiological marker for PAS. A flow duration under 7 min reliably excludes PAS, while durations exceeding 14 min strongly suggest its presence. Incorporating this marker into intraoperative decision-making may enhance preparedness and maternal safety during caesarean delivery for placenta praevia. placenta accreta spectrum placenta praevia caesarean section intraoperative ultrasonography cervical varicosity transvaginal ultrasonography multidisciplinary team hysterectomy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Background Accurate risk assessment of placenta accreta spectrum (PAS) in cases of placenta praevia is critical for safe surgical management. Although prenatal diagnosis of PAS has improved with advances in imaging technologies, no standardized method currently exists for intraoperative assessment. In particular, there is limited evidence regarding real-time intraoperative evaluation of placental blood flow using ultrasonography. Previous studies have primarily focused on enhancing preoperative prediction through detailed imaging [1–3]. The introduction of magnetic resonance imaging (MRI) has enabled a more comprehensive assessment, including quantification of cervical varicosities [4,5]. Practical and reproducible ultrasound-based scoring systems with favorable sensitivity and specificity have also demonstrated increasing clinical utility [6–8]. Preoperative planning requires the integration of imaging findings with clinical risk factors to predict PAS and the risk of massive haemorrhage, facilitating preparation for severe complications [9,10]. Such preparation includes establishing perioperative strategies involving massive transfusion protocols, interventional radiology, and multidisciplinary specialist teams [11]. However, when unexpected placental adherence is encountered intraoperatively, forceful manual removal or delays in achieving haemostasis can lead to serious complications. Inadequate preparation may result in delayed management and worsened maternal outcomes [12]. Moreover, intraoperative decision-making regarding PAS management, including the consideration of hysterectomy, requires experienced personnel and infrastructure to support timely clinical judgment [13, 14]. In patients with placenta praevia, careful assessment of abnormal placental attachment is essential, and surgical approaches must be guided by the risk of PAS [10]. Given that PAS frequently involves the region near the internal cervical os in placenta praevia [15,16], transvaginal ultrasonography (TVUS) offers practical advantages for intraoperative use. However, no studies have evaluated intraoperative blood flow at the placental attachment site or its association with PAS. The clinical significance of such haemodynamic assessments remains unclear. Methods The Aim This study aimed to evaluate intraoperative temporal changes in blood flow within cervical varicosities using ultrasonography and to examine their association with PAS. We further assessed the predictive accuracy of blood flow duration for PAS and explored optimal cut-off values to determine the clinical utility of this method in facilitating early intraoperative diagnosis and management of PAS. Study design This retrospective observational study included patients diagnosed with placenta praevia who delivered at Okayama University Hospital (Okayama, Japan) between January 2017 and June 2024. Clinical data were obtained from electronic medical records, conference documentation, operative notes, and surgical video recordings. The study was approved by the Ethics Committee of Okayama University Hospital (Approval No.: 2409-047), and relevant information was disclosed to eligible patients via an opt-out approach. Among the 3,080 deliveries that occurred at our institution during the study period, we included patients who met the following criteria: singleton pregnancy, age ≥18 years, diagnosis of placenta praevia, delivery by caesarean section, and availability of intraoperative TVUS data for blood flow assessment. Medical records, conference materials, surgical reports, and intraoperative videos were reviewed for all eligible patients. Exclusion criteria were multiple pregnancies, caesarean deliveries performed entirely under general anaesthesia from the outset of the procedure, absence of intraoperative TVUS blood flow recordings or documentation, stillbirths, marginal placenta praevia, and low-lying placenta. Preoperative Risk Assessment for PAS in Placenta Praevia Placenta praevia was defined as a condition in which the placenta completely or partially covered the internal cervical os [17]. In cases diagnosed with placenta praevia via TVUS prior to 32 weeks of gestation during routine antenatal check-ups, further detailed assessment of placental adherence was undertaken at approximately 33 weeks using both MRI and TVUS. MRI findings suggestive of abnormal placental adherence were interpreted by certified radiologists and included the presence of dark intraplacental bands on T2-weighted images, heterogeneous placental signal intensity, indistinct borders between the placenta and myometrium, myometrial thinning or interruption, and focal uterine bulging [1,18-20]. Additionally, based on the method proposed by Ishibashi et al. for predicting PAS using the ratio of cervical varicosity depth to placental thickness, sagittal T2-weighted images including the internal cervical os were used [4, 5, 21]. To quantify cervical varicosities, we calculated the A/B ratio [4], where “A” represented the shortest distance from the most posterior cervical varicosity to the decidual surface of the placenta, and “B” represented the shortest distance from the same varicosity to the amniotic side of the placenta (Figure 1). In cases where the multidisciplinary team assessed a high risk of PAS and considered hysterectomy likely, preoperative preparations such as ureteric stent placement or temporary balloon occlusion of the internal iliac arteries were carried out immediately prior to surgery. In all such cases, 300–900 mL of autologous blood was prepared in advance. Primary Outcome Measurement (Intraoperative Transvaginal Ultrasound Assessment of Cervical Blood Flow) The primary outcome of this study was the intraoperative evaluation of blood flow using TVUS. Patients were placed in the lithotomy position, with a dedicated ultrasound examiner positioned between the legs. A transvaginal probe (5–9 MHz; Canon Aplio i800, Tokyo, Japan) was used. In the sagittal plane on greyscale imaging, the target imaging plane was defined as the plane showing the cervical line extending from the external to the internal cervical os. Within this plane, colour flow signals corresponding to cervical varicosities located between the placenta and myometrium were assessed (Figure 2). Colour Doppler mode was employed to detect low-velocity blood flow (2.0–12.0 cm/s), using the preoperative colour flow signal as a reference. Intraoperatively, continuous observation of cervical varicosities was conducted from fetal delivery until placental delivery. The duration of detectable blood flow—referred to as the blood flow persistence time—was defined as the interval from fetal delivery to the disappearance of the colour flow signal (velocity ≤ 2.0 cm/s), based on the preoperative reference. A velocity threshold of ≤ 2.0 cm/s was selected because, at this level, colour flow signals typically become undetectable in Colour Doppler mode due to technical limitations in visualising very low-velocity flow. Thus, this value serves as a practical indicator of blood flow cessation in patients with cervical varicosities. The blood flow persistence time was recorded in minutes. Each case was retrospectively reviewed using operative video footage and surgical records. Two obstetricians specialising in perinatal medicine independently measured the blood flow persistence time. Interobserver agreement was assessed using the kappa coefficient. In cases of discrepancy between observers, the mean of the two measurements was used. For cases in which blood flow persisted beyond 40 minutes, the persistence time was uniformly recorded as 40 minutes. Two representative cases demonstrating the duration of blood flow within cervical varicosities—one diagnosed with PAS and one without—are presented as supplementary videos in Videoclip S1. Diagnosis of PAS The presence or absence of PAS was assessed based on clinical and pathological findings, in accordance with the International Federation of Gynaecology and Obstetrics (FIGO) classification system [22]. PAS was defined as grade 1 (placenta accreta), grade 2 (placenta increta), or grade 3 (placenta percreta: 3a, 3b, and 3c). The diagnosis was made based on intraoperative findings—such as difficulty in placental removal—documented in surgical records, and/or histopathological confirmation of PAS. All pathological evaluations were performed by certified pathologists. Major Adverse Outcome The primary adverse outcome assessed in this study was peripartum hysterectomy. No maternal deaths related to placenta praevia occurred during the study period. Other Outcomes Additional clinical data collected included maternal age at delivery, parity, mode of conception, pregnancy-related complications, gestational age at delivery, medical and surgical history (including prior PAS, uterine surgeries, dilatation and curettage, and endometriosis), smoking history, additional interventions for haemostasis, and estimated intraoperative blood loss. Statistical Analysis The required sample size was estimated through power analysis to evaluate diagnostic accuracy. Assuming an expected area under the curve (AUC) of 0.80, a null hypothesis AUC of 0.60, a significance level of 0.05, and a statistical power of 90%, the minimum number of required cases was calculated to be 33, based on an assumed 1:2 ratio of PAS-positive to PAS-negative cases. Receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of intraoperative cervical varicosity blood flow persistence time in predicting PAS in patients with placenta praevia. Blood flow persistence times beginning at 6 minutes were assessed at one-minute intervals to evaluate the sensitivity, specificity, and predictive values associated with each threshold. The optimal cut-off value was determined using the Youden index, and the corresponding sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. For the multivariable analysis, logistic regression was conducted using blood flow persistence time, history of caesarean section, mode of conception, and preoperative PAS prediction (MRI A/B ratio) as covariates. There were no missing data regarding patient demographic characteristics or primary outcome measures. However, a small number of cases had missing values for the MRI-based preoperative PAS assessment. Given the non-essential nature of these variables in the primary analysis and the relatively small proportion of missing data, no imputation was performed. Cases with missing MRI data were excluded from analyses involving MRI findings. All statistical analyses were conducted using SAS V.9.4 TS1M8 (SAS Institute, Cary, NC, USA), while sensitivity analyses and figure generation were performed using Python (v3.10.12). Sensitivity Analyses Two sensitivity analyses were conducted to evaluate the robustness of our findings. In the first analysis, cases of increta and percreta were excluded in order to assess diagnostic accuracy specifically for placenta accreta. ROC analysis was repeated using only accreta cases as the positive group. In the second analysis, the primary analysis was repeated after including cases that had initially been excluded due to general anaesthesia or marginal placenta praevia, to examine the impact of these exclusion criteria on diagnostic performance. Result Study Population and Baseline Characteristics Among the patients who underwent caesarean section for placenta praevia, 76 cases were initially identified. After excluding 24 patients based on predefined criteria, 52 were included in the final analysis (Figure 3). Table 1 summarises the maternal characteristics and clinical outcomes stratified by the presence or absence of PAS. The mean maternal age across all cases was 34.45 ± 4.97 years, and 24 of the 52 patients (46.2%) were nulliparous. PAS was diagnosed in 20 of the 52 patients (38.5%). Among those with PAS, a history of prior caesarean delivery was observed in 7 of 20 cases (35.0%), and a history of endometrial curettage was reported in 8 of 20 patients (40.0%). Regarding the mode of conception, in vitro fertilisation (IVF) was more frequent in the PAS group (8 of 20; 40.0%) than in the non-PAS group (6 of 32; 18.8%), indicating a tendency towards higher prevalence in the PAS group. MRI A/B ratios were lower in the PAS group (0.26 ± 0.13) than in the non-PAS group (0.38 ± 0.13). The mean duration of cervical varicosity blood flow, measured from fetal delivery, was 11.09 ± 11.64 minutes across all cases. In the PAS group, the duration was significantly longer, with a mean of 20.20 ± 14.31 minutes, compared to 5.69 ± 2.46 minutes in the non-PAS group. The interobserver agreement for the assessment of blood flow duration was substantial, with a kappa coefficient of 0.67. Hysterectomy was performed in 7 of the 52 cases (13.5%), all of which occurred in the PAS group. Diagnostic Accuracy of Blood Flow Persistence Time for PAS Figure 4 presents the ROC curve assessing the diagnostic performance of cervical varicosity flow duration for the diagnosis of PAS. The AUC was 0.94, and the optimal cut-off was 7 minutes. Table 2 summarises the diagnostic performance metrics for cut-off values ranging from 6 to 15 minutes. At the 7-minute threshold, sensitivity was 1.00, specificity was 0.72, the PPV was 0.69, and the NPV was 1.00. At 11 minutes, sensitivity decreased to 0.55, specificity increased to 0.97, PPV was 0.92, and NPV was 0.78. A blood flow persistence time of ≥11 minutes was highly predictive of PAS. Furthermore, a duration exceeding 14 minutes was observed in only a limited number of PAS cases but demonstrated a PPV of 1.00. The ROC curve in Figure 5 reflects the results of the multivariable analysis, which included cervical vascular flow duration alongside clinical and imaging predictors, demonstrating high diagnostic accuracy for PAS. The AUC following multivariate analysis was 0.95. The optimal cut-off value for blood flow duration was 8 minutes, with a sensitivity of 0.95 and specificity of 0.91. Predictive Value for Hysterectomy The diagnostic performance of blood flow persistence time for predicting peripartum hysterectomy was evaluated, and the results are summarised in Table 3. At a cut-off of 7 minutes, the sensitivity was 1.00, specificity was 0.51, the PPV was 0.24, and the NPV was 1.00. Specificity improved to 0.93 at a cut-off of 13 minutes. When the threshold was set at ≥15 minutes, sensitivity remained at 1.00, specificity increased to 0.96, PPV was 0.78, and NPV remained at 1.00. Sensitivity analysis For cases restricted to placenta accreta, the AUC was 0.92, with the optimal cut-off point being 7 minutes; a flow duration exceeding 14 minutes yielded a PPV of 1.00 (Table 4, Figure 6). When cases involving general anaesthesia and marginal placenta praevia were included, the AUC remained high at 0.95, with an optimal cut-off of 8 minutes, consistent with the main analysis (Table 5, Figure7). Discussion This study evaluated the clinical utility of real-time TVUS as an intraoperative diagnostic aid for PAS, focusing on the assessment of blood flow within cervical varicosities during caesarean section for placenta praevia. A blood flow duration of less than 7 minutes was consistently associated with the absence of PAS, thereby supporting standard placental management with confidence. In contrast, a duration of ≥11 minutes demonstrated a strong association with PAS (PPV = 0.92), and all cases with flow lasting ≥14 minutes fulfilled the FIGO diagnostic criteria for PAS (PPV = 1.00). These thresholds provide an objective and actionable parameter to guide intraoperative decision-making. When blood flow persists beyond 7 minutes, a brief pause and team reassessment may facilitate timely preparation for escalated interventions, such as hysterectomy or massive transfusion, while minimising the risk of hasty or forceful placental separation. In the absence of PAS, placental separation occurs along the decidual interface, leading to the physiological collapse of maternal–fetal vascular shunts, including spiral artery flow. This results in the rapid cessation of blood flow within the uterine wall and cervical vascular layers [23-25]. In contrast, the physiological rationale for persistent flow in PAS aligns with established pathophysiological mechanisms. In PAS, failure of normal decidualisation permits direct invasion of trophoblasts into the myometrium, serosa, or adjacent organs, resulting in the formation of abnormal arteriovenous communications between maternal and placental circulations [25,26]. These pathological shunts often remain patent even after attempts at placental separation, allowing for sustained perfusion. Particularly in the lower uterine segment and cervix—where collateral venous pathways such as the paracervical and parametrial plexuses are often well developed—blood flow may be maintained through both placental and extraplacental vascular supplies. Our intraoperative observations of persistent low-velocity blood flow likely reflect these underlying structural and haemodynamic abnormalities in real time, and may serve as a non-invasive physiological surrogate for pathological invasion in PAS. In this context, the persistence time of cervical varicosities represents a reproducible, physiological, and temporally responsive marker that can be assessed dynamically and non-invasively. Unlike static imaging features such as placental lacunae or myometrial thinning [7,18], flow duration permits continuous monitoring throughout the procedure, providing valuable intraoperative feedback as the surgical situation evolves. This is particularly advantageous when preoperative imaging findings are equivocal, inconsistent, or unavailable. Importantly, the present study highlights the inherent limitations of relying exclusively on preoperative imaging for the diagnosis of PAS. Conventional ultrasonographic indicators—such as the presence of multiple placental lacunae, discontinuity of the bladder wall, and attenuation or absence of the hypoechoic myometrial zone [1,3,6,7]—as well as more recent MRI features—including dark intraplacental bands on T2-weighted sequences, focal bulging of the uterine contour, and disruption of the uterine–placental interface [2,7]—have improved diagnostic accuracy. However, these findings are not universally present in all affected cases. Moreover, interobserver variability and institutional differences in diagnostic experience may undermine the consistency of preoperative assessments. Such variability in risk stratification may contribute to suboptimal intraoperative management, including unnecessary uterine manipulation, delayed decisions regarding hysterectomy, or an increased risk of severe haemorrhage [12]. Several factors are known to contribute to adverse outcomes in cases of unexpected PAS, including delayed recognition, unplanned responses to haemorrhage, the use of inappropriate surgical techniques (e.g., forceful placental removal), poor intra-team communication, and insufficient preparation [13,27]. Intraoperative uncertainty often gives rise to confusion and panic, increasing the likelihood of maternal morbidity. An objective marker such as cervical blood flow duration could help bridge this gap by aligning team understanding, reducing cognitive bias, and supporting shared decision-making in real time. Notably, real-time intraoperative metrics are rare in obstetric surgery, and the introduction of a practical and reproducible marker represents a meaningful contribution to the field. Strengths and Limitations This study is the first to evaluate blood flow duration as an intraoperative predictor of PAS. By quantifying a physiological parameter using the widely available TVUS, we propose a practical tool that may support intraoperative decision-making and enhance surgical safety. However, it is important to acknowledge that the recommended intraoperative responses based on specific blood flow duration thresholds were developed within the context of our institution’s patient population and surgical protocols. Therefore, these strategies may not be generalisable to all clinical settings. To support potential adaptation in other institutions, detailed decision-making pathways and intraoperative management algorithms are provided in Table 6. Nonetheless, this study has several limitations. First, it was a retrospective, single-centre study, which may limit the generalisability of the findings. Second, although efforts were made to standardise the measurement of flow duration, the final classification relied on consensus between two experienced obstetricians, introducing a degree of subjectivity. Moreover, surgical outcomes such as hysterectomy were influenced not only by blood loss and placental adherence but also by surgeon experience, urgency of the case, and patient comorbidities. These confounding factors may affect the strength of the association between flow duration and clinical outcomes. Future prospective, multicentre studies are warranted to validate these findings and establish standardised thresholds for clinical use. In addition, efforts to automate and quantify flow duration using software or integrated Doppler imaging systems may further enhance reproducibility. Ultimately, the integration of cervical varicosity blood flow monitoring into obstetric surgical protocols may provide a simple, non-invasive, and effective strategy to improve maternal safety and refine intraoperative diagnosis and management of PAS. Conclusion The intraoperative assessment of blood flow duration within cervical varicosities using TVUS offers a reproducible and physiologically meaningful marker suggestive of PAS in patients with placenta praevia. The cessation of low-velocity flow within 7 minutes following fetal delivery reliably excludes PAS, whereas persistent flow of 14 minutes or more is highly suggestive of its presence. Incorporating this objective parameter into intraoperative decision-making may facilitate risk stratification, optimise surgical planning, and ultimately improve maternal safety during caesarean delivery for placenta praevia. Abbreviations AUC – Area Under the Curve FIGO – International Federation of Gynaecology and Obstetrics IVF – In Vitro Fertilisation MRI – Magnetic Resonance Imaging NPV – Negative Predictive Value PAS – Placenta Accreta Spectrum PPV – Positive Predictive Value ROC – Receiver Operating Characteristic TVUS – Transvaginal Ultrasonography Declarations Ethics approval and consent to participate This study was approved by the Ethics Committee of Okayama University Hospital (Approval No.: 2409-047). In accordance with institutional policy, information regarding the study was disclosed to eligible patients via an opt-out approach, and consent was obtained accordingly. Consent for publication Not applicable. Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Authors' contributions The authors confirm their individual contributions to the study as follows: TM: Conceptualization, Investigation, Data Curation, Visualization, Writing Formal Analysis, Writing – Original Draft SS: Investigation, Data Curation, Supervision, Resources AS: Investigation, Data Curation, Validation HO: Data Curation, Statistical support, Investigation KH: Supervision, Data Curation, Validation, Investigation – Review JM: Conceptualization, Methodology, Statistical advice – Review & Editing All authors read and approved the final manuscript. Acknowledgments We would like to express our sincere gratitude to all healthcare professionals involved in the multidisciplinary management of placenta praevia surgeries. In particular, we extend our appreciation to the midwives, nurses, anaesthetists, radiologists, clinical engineers, and paediatricians at Okayama University Hospital for their dedicated support and collaboration. Their expertise and commitment have been invaluable in ensuring the safety and quality of peripartum care. We also thank Chiaki Kuriyama, Hikari Nakato, Kazumasa Kato, Sakurako Mishima, Akiko Ohira, Stoe Kirino, Eriko Eto, and Hisashi Masuyama for their valuable contributions to clinical practice and academic guidance. We gratefully acknowledge the financial support provided by Okayama University for the open access publication of this work. Details of Ethics Approval This study was approved by the Ethics Committee of Okayama University Hospital (Approval No.: 2409-047 ). The requirement for written informed consent was waived due to the retrospective nature of the study, and information about the study was disclosed publicly in accordance with the opt-out policy approved by the ethics committee. The study was conducted in accordance with the principles of the Declaration of Helsinki. No clinical trial registration was required, as this was a retrospective observational study. No animals were involved in this study. References Maurea S, Verde F, Romeo V, Stanzione A, Mainenti PP, Raia G, et al. Prediction of placenta accreta spectrum in patients with placenta previa using a clinical, US and MRI combined model: A retrospective study with external validation. Eur J Radiol. 2023 Nov;168:111116. Balcacer P, Pahade J, Spektor M, Staib L, Copel JA, McCarthy S. Magnetic Resonance Imaging and Sonography in the Diagnosis of Placental Invasion. J Ultrasound Med. 2016 Jul;35(7):1445-56. 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Jauniaux E, Ayres-de-Campos D, Langhoff-Roos J, Fox KA, Collins S; FIGO Placenta Accreta Diagnosis and Management Expert Consensus Panel. FIGO classification for the clinical diagnosis of placenta accreta spectrum disorders. Int J Gynaecol Obstet. 2019 Jul;146(1):20-24. Herman A, Zimerman A, Arieli S, Tovbin Y, Bezer M, Bukovsky I, et al. Down-up sequential separation of the placenta. Ultrasound Obstet Gynecol. 2002 Mar;19(3):278-81. Gusella A, Martignoni G, Giacometti C. Behind the Curtain of Abnormal Placentation in Pre-Eclampsia: From Molecular Mechanisms to Histological Hallmarks. Int J Mol Sci. 2024 Jul 18;25(14):7886. Krapp M, Baschat AA, Hankeln M, Gembruch U. Gray scale and color Doppler sonography in the third stage of labor for early detection of failed placental separation. Ultrasound Obstet Gynecol. 2000 Feb;15(2):138-42. Jauniaux E, Collins S, Burton GJ. Placenta accreta spectrum: pathophysiology and evidence-based anatomy for prenatal ultrasound imaging. Am J Obstet Gynecol. 2018 Jan;218(1):75-87. Erfani H, Fox KA, Clark SL, Rac M, Rocky Hui SK, Rezaei A, et al. Maternal outcomes in unexpected placenta accreta spectrum disorders: single-center experience with a multidisciplinary team. Am J Obstet Gynecol. 2019 Oct;221(4):337.e1-337.e5. Tables Table 1. Comparison of clinical characteristics according to the presence of placenta accreta spectrum PAS (+) PAS (-) n=20 n=32 Age, mean years, SD 35.75 5.47 33.94 4.96 Parity, n, % Primiparous 8 40 16 50 Multiparous 12 60 16 50 Gynecological history, n, % Cesarean section 7 35 7 22 Placenta previa 2 10 1 3 Myomectomy 5 25 3 9 Endometrial curettage 8 40 7 22 Endometriosis 2 10 4 13 Conception, n, % Spontaneous conception 12 60 25 78 Intrauterine insemination 0 0 1 3 In vitro fertilization 8 40 6 19 Course of pregnancy, n, % Sentinel bleeding 12 60 18 56 Gestational diabetes mellitus 3 15 2 6 Pregnancy with uterine fibroids 5 25 5 16 Placental location, n, % Anteriorly dominant 9 45 7 22 Posteriorly dominant 11 55 25 78 Preoperative adhesion assessment MRI-suspected adhesions*, n, % 14 74 9 31 MRI-based A/B score of cervical varicosities†, mean score, SD 0.26 0.13 0.40 0.14 Intraoperative findings Bleeding, ml, SD 2523 2037 1594 711 Time to disappearance of blood flow within cervical varicosities, mean, SD 20.20 14.31 5.69 2.46 Placental delivery time, mean min, SD 23.04 22.11 8.52 5.41 Intraoperative interventions Manual placental removal, n, % 6 30 1 3.1 Bipolar vessel sealing device, n, % 6 30 5 15.6 Hemostatic suturing, n, % 6 30 12 37.5 Compression suture, n, % 2 10 4 12.5 Intrauterine balloon tamponade, n, % 10 50 12 37.5 Outcome Hysterectomy, n, % 7 35 0 0 Placenta accreta spectrum classification FIGO Ⅰ(accreta) 16 80 - - FIGO Ⅱ(inccreta) 2 10 - - FIGO Ⅲ(percreta) 2 10 - - Abbreviation; FIGO, International Federation of Gynecology and Obstetrics; MRI, magnetic resonance image; PAS, placenta accreta spectrum; SD, standard deviation; * In the MRI examination, the presence of any one of the following four indicators suggestive of placenta accreta spectrum was considered to indicate a risk of placental adhesion:dark T2-weighted intraplacental bands, heterogeneous signals in the placenta, myometrial thinning or interruption, and focal uterine bulging. † Cervical varicosities were evaluated using T2-weighted sagittal images including the internal cervical os. The minimum distance from the most dorsal cervical varicosities to (A) the decidual (placental) side and (B) the amniotic side was measured and used for scoring. Table 2. Cut-off levels of blood flow persistence time for the occurrence of placenta accreta spectrum. cutoff value for blood flow persistence time* (min) Sensitivity Specificity Positive predictive value Negative predictive value 6 1.00 0.59 0.61 1.00 7 1.00 0.72 0.69 1.00 8 0.9 0.81 0.75 0.93 9 0.75 0.88 0.79 0.85 10 0.75 0.91 0.83 0.85 11 0.55 0.97 0.92 0.78 12 0.55 0.97 0.92 0.78 13 0.45 0.97 0.9 0.74 14 0.45 1.00 1.00 0.74 15 0.45 1.00 1.00 0.74 *It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal Table 3. Cutoff levels of blood flow persistence time for the occurrence of total abdominal hysterectomy. Cutoff value for blood flow persistence time* (min) Sensitivity Specificity Positive predictive value Negative predictive value 6 1.00 0.42 0.21 1.00 7 1.00 0.51 0.24 1.00 8 1.00 0.62 0.29 1.00 9 1.00 0.73 0.37 1.00 10 1.00 0.76 0.39 1.00 11 1.00 0.89 0.58 1.00 12 1.00 0.89 0.58 1.00 13 1.00 0.93 0.7 1.00 14 1.00 0.96 0.78 1.00 15 1.00 0.96 0.78 1.00 16 1.00 1.00 1.00 1.00 *It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal Table 4. Sensitivity analysis of blood flow signal duration cutoff levels for diagnosing placenta accreta, excluding placenta increta and percreta cases. Cutoff value for blood flow duration* (min) Sensitivity Specificity Positive predictive value Negative predictive value 6 1.00 0.59 0.55 1.00 7 1.00 0.72 0.64 1.00 8 0.88 0.81 0.70 0.93 9 0.69 0.88 0.73 0.85 10 0.69 0.91 0.79 0.85 11 0.44 0.97 0.88 0.78 12 0.44 0.97 0.88 0.78 13 0.31 0.97 0.83 0.74 14 0.31 1.00 1.00 0.74 15 0.31 1.00 1.00 0.74 *It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal Table 5. Sensitivity Analysis of Blood Flow Signal Cutoff Levels After Modification of Eligibility Criteria* Cut-off value for blood flow duration† (min) Sensitivity Specificity Positive predictive value Negative predictive value 6 1.00 0.60 0.58 1.00 7 1.00 0.72 0.66 1.00 8 0.91 0.81 0.72 0.95 9 0.78 0.91 0.82 0.89 10 0.78 0.93 0.86 0.89 11 0.61 0.98 0.93 0.82 12 0.61 0.98 0.93 0.82 13 0.48 0.98 0.92 0.78 14 0.48 1.00 1.00 0.78 15 0.48 1.00 1.00 0.78 *The main analysis was repeated after including cases that were initially excluded due to general anesthesia or marginal placenta previa, in order to examine the impact of these exclusion criteria on diagnostic performance. † It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal Table 6. Recommended intraoperative management steps based on cervical blood flow persistence time during cesarean section for placenta previa. Flow duration range Clinical interpretation Recommended intraoperative actions Notes < 7 min Low likelihood of PAS Proceed with standard surgical procedure. Avoid unnecessary placental separation to ensure safety. High negative predictive value (NPV). 7–11 min Intermediate zone; moderate risk of PAS Initiate intraoperative team huddle. Reassess surgical field. Prepare for hemostasis, blood transfusion, and consider potential need for TAH. Communicate with anesthesia and transfusion teams. Surgical reassessment and team coordination needed. 11–14 min High likelihood of PAS (PPV ≈ 92%) Promptly notify anesthesiology and transfusion teams. Begin transfusion and prepare for surgical hemostasis. Reconfirm role assignments among surgical team. Immediate action is critical. ≥14 min PAS almost certain (PPV = 100%) Prepare for TAH or staged surgery. Consider operator replacement and request experienced surgical backup. Ensure rapid team communication and coordination of intraoperative management. All cases with ≥14 min was confirmed PAS. Additional Declarations No competing interests reported. Supplementary Files PASprevia.mp4 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6938564","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":477831789,"identity":"cb2ae3ea-5a00-426b-8dcd-c3f81290bcdb","order_by":0,"name":"Tomohiro Mitoma","email":"","orcid":"","institution":"Okayama University","correspondingAuthor":false,"prefix":"","firstName":"Tomohiro","middleName":"","lastName":"Mitoma","suffix":""},{"id":477831791,"identity":"742a887b-48ed-4cf9-9ec6-7df6740dc905","order_by":1,"name":"Shujiro Sakata","email":"","orcid":"","institution":"Okayama University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Shujiro","middleName":"","lastName":"Sakata","suffix":""},{"id":477831792,"identity":"b351b9da-9c76-443a-a6fc-57e8047fd956","order_by":2,"name":"Ayano Suemori","email":"","orcid":"","institution":"Okayama University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Ayano","middleName":"","lastName":"Suemori","suffix":""},{"id":477831795,"identity":"bffe595c-d73b-45ec-a2be-6137399bce42","order_by":3,"name":"Hikaru Ooba","email":"","orcid":"","institution":"Okayama University","correspondingAuthor":false,"prefix":"","firstName":"Hikaru","middleName":"","lastName":"Ooba","suffix":""},{"id":477831796,"identity":"63745b3c-8446-4711-accc-daf00c8a9d5a","order_by":4,"name":"Kei Hayata","email":"","orcid":"","institution":"Fukuyama city hospital","correspondingAuthor":false,"prefix":"","firstName":"Kei","middleName":"","lastName":"Hayata","suffix":""},{"id":477831800,"identity":"09efdd1d-940a-4f5d-a829-22622a6246f4","order_by":5,"name":"Jota Maki","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABDklEQVRIiWNgGAWjYBACxgYwlcDDz8CGIsGGRTFMCzNEi2QDsVoYGCBaGAwO4FOEoqG9/+CnGzVpMsbH2xI/89Rsk2eQSGD88IOBLw+nw3oOM0vnHMvhMTtz7LA0z7Hbhg0SCcySPQxsxTi1zEhmkM5hq+Axu5HeIM3Ddptx/40EBmmgXxIbcGth/p3zr4LHeEZ682+ef7ftQbb8JqCFTTq3LYfHQCLtmDRv2+1EoBY2/Lb0HDazzu1L45E4cyzNcm7f7eQGnodtlj0GuP1i2N74+HbOt2R7/vY24xtvvt22bWBPPnzjR8UxnCFmiGw9Ew/EZqCYwbEEXFrkUVz5A8GuwallFIyCUTAKRhwAAMvVU+/GeM5sAAAAAElFTkSuQmCC","orcid":"","institution":"Okayama University","correspondingAuthor":true,"prefix":"","firstName":"Jota","middleName":"","lastName":"Maki","suffix":""}],"badges":[],"createdAt":"2025-06-20 11:38:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6938564/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6938564/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85824418,"identity":"029fee57-319b-44d3-b556-18356f795de7","added_by":"auto","created_at":"2025-07-02 07:02:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2934096,"visible":true,"origin":"","legend":"\u003cp\u003eImaging of Cervical Varicosities During Pregnancy: TVUS and MRI Findings\u003c/p\u003e\n\u003cp\u003eThese images include sagittal T2-weighted MRI scans (a and b) obtained at 33 weeks of gestation and transvaginal ultrasonographic images (c and d) acquired at 35 weeks in a patient with placenta previa. The region outlined by the white dashed line in panels b) and d) represents the cervical varicosity, which was defined based on its characteristic vascular morphology along the cervical canal. The positional relationship between the cervical varicosity, the placenta, and the serosal surface is indicated as A/B.\u003c/p\u003e","description":"","filename":"Figure111.png","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/4414d518078e4ce165b10f54.png"},{"id":85823734,"identity":"806c309e-b1fa-4b76-8504-0db61fc11fad","added_by":"auto","created_at":"2025-07-02 06:54:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":4183645,"visible":true,"origin":"","legend":"\u003cp\u003eReal-time Colour Doppler Imaging of Cervical Varicosities at the Beginning of Caesarean Section in a Case of Placenta Praevia\u003cbr\u003e\nPanels \u003cstrong\u003ea\u003c/strong\u003e and \u003cstrong\u003eb\u003c/strong\u003e show transvaginal ultrasonographic images obtained at the start of surgery, prior to fetal delivery, captured within the same time frame. Blood flow within the cervical varicosity is assessed in the sagittal plane using colour Doppler mode. Panel \u003cstrong\u003eb\u003c/strong\u003e includes colour overlays to illustrate anatomical orientation.\u003c/p\u003e","description":"","filename":"Figure28.png","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/a7d65a8af5df0d6eddd66aad.png"},{"id":85824416,"identity":"0f7d9b81-3c0a-4182-b868-25fbdc30c8bd","added_by":"auto","created_at":"2025-07-02 07:02:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":719880,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of the Study Design\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/46bd55e25874473b547ab84b.png"},{"id":85823730,"identity":"65c46ca1-f1de-49d5-8c33-a9215f220070","added_by":"auto","created_at":"2025-07-02 06:54:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":98792,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver Operating Characteristic Curve for the Prediction of Placenta Accreta Spectrum Based on Cervical Varicosity Blood Flow Persistence Time\u003cbr\u003e\nROC curve illustrating the diagnostic performance of cervical varicosity blood flow persistence time in predicting the presence of placenta accreta spectrum.\u003c/p\u003e","description":"","filename":"Figure46.png","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/cb3fc773db863ece8ca5854b.png"},{"id":85823729,"identity":"d8d76e2d-3cbd-4bd3-8c24-90063517b00a","added_by":"auto","created_at":"2025-07-02 06:54:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":94626,"visible":true,"origin":"","legend":"\u003cp\u003eMultivariable ROC Curve for the Prediction of Placenta Accreta Spectrum Using Blood Flow Persistence Time and Clinical Covariates\u003c/p\u003e\n\u003cp\u003eMultivariate receiver operating characteristic curve assessing the diagnostic accuracy of a model predicting placenta accreta spectrum (PAS). The model incorporated cervical varicosity blood flow persistence time, history of cesarean section, mode of conception, and preoperative PAS prediction based on MRI A/B ratio as covariates.\u003c/p\u003e","description":"","filename":"Figure52.png","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/4d04a3f5e26032ba0c7cfabb.png"},{"id":85823733,"identity":"e1d7fd46-79d9-4e9c-8f88-b9d10e1b8e31","added_by":"auto","created_at":"2025-07-02 06:54:39","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":243986,"visible":true,"origin":"","legend":"\u003cp\u003eROC Curve for the Diagnosis of Placenta Accreta After Excluding Increta and Percreta Cases\u003c/p\u003e\n\u003cp\u003eReceiver operating characteristic (ROC) curve analysis repeated to assess the diagnostic accuracy of cervical varicosity blood flow persistence time for identifying placenta accreta, excluding cases of increta and percreta. The analysis was performed to isolate diagnostic performance for the most conservative form of placenta accreta spectrum.\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/210184608e9ccff45ae76023.jpg"},{"id":85825867,"identity":"7ffcc44d-9210-4e81-9b9c-13a8cc33d1ee","added_by":"auto","created_at":"2025-07-02 07:10:39","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":99346,"visible":true,"origin":"","legend":"\u003cp\u003eSensitivity Analysis Including Cases Initially Excluded Due to General Anesthesia or Marginal Placenta Previa\u003c/p\u003e\n\u003cp\u003eROC curve analysis repeated to evaluate the robustness of the diagnostic performance of cervical varicosity blood flow persistence time. This sensitivity analysis included cases that were initially excluded from the main analysis due to general anesthesia at the time of surgery or a diagnosis of marginal placenta previa. The aim was to assess the potential impact of these exclusion criteria on overall diagnostic accuracy.\u003c/p\u003e","description":"","filename":"Figure7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/b10fdc3ba309323d6c17f874.jpg"},{"id":89815245,"identity":"db411e5f-b369-4a67-8f23-95c5e0b17ebd","added_by":"auto","created_at":"2025-08-25 10:32:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11371420,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/660cd766-6dd5-4395-93f3-84503068d84f.pdf"},{"id":85823777,"identity":"4bfe2885-6725-44ac-87ba-2e5f48825ab8","added_by":"auto","created_at":"2025-07-02 06:54:54","extension":"mp4","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":292948736,"visible":true,"origin":"","legend":"","description":"","filename":"PASprevia.mp4","url":"https://assets-eu.researchsquare.com/files/rs-6938564/v1/89f8cc5e4b5ca703f58eb894.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: a retrospective observational study","fulltext":[{"header":"Background","content":"\u003cp\u003eAccurate risk assessment of placenta accreta spectrum (PAS) in cases of placenta praevia is critical for safe surgical management. Although prenatal diagnosis of PAS has improved with advances in imaging technologies, no standardized method currently exists for intraoperative assessment. In particular, there is limited evidence regarding real-time intraoperative evaluation of placental blood flow using ultrasonography.\u003c/p\u003e\n\u003cp\u003ePrevious studies have primarily focused on enhancing preoperative prediction through detailed imaging [1\u0026ndash;3]. The introduction of magnetic resonance imaging (MRI) has enabled a more comprehensive assessment, including quantification of cervical varicosities [4,5]. Practical and reproducible ultrasound-based scoring systems with favorable sensitivity and specificity have also demonstrated increasing clinical utility [6\u0026ndash;8]. Preoperative planning requires the integration of imaging findings with clinical risk factors to predict PAS and the risk of massive haemorrhage, facilitating preparation for severe complications [9,10]. Such preparation includes establishing perioperative strategies involving massive transfusion protocols, interventional radiology, and multidisciplinary specialist teams [11]. However, when unexpected placental adherence is encountered intraoperatively, forceful manual removal or delays in achieving haemostasis can lead to serious complications. Inadequate preparation may result in delayed management and worsened maternal outcomes [12]. Moreover, intraoperative decision-making regarding PAS management, including the consideration of hysterectomy, requires experienced personnel and infrastructure to support timely clinical judgment [13, 14]. In patients with placenta praevia, careful assessment of abnormal placental attachment is essential, and surgical approaches must be guided by the risk of PAS [10]. Given that PAS frequently involves the region near the internal cervical os in placenta praevia [15,16], transvaginal ultrasonography (TVUS) offers practical advantages for intraoperative use. However, no studies have evaluated intraoperative blood flow at the placental attachment site or its association with PAS. The clinical significance of such haemodynamic assessments remains unclear.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eThe Aim\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study aimed to evaluate intraoperative temporal changes in blood flow within cervical varicosities using ultrasonography and to examine their association with PAS. We further assessed the predictive accuracy of blood flow duration for PAS and explored optimal cut-off values to determine the clinical utility of this method in facilitating early intraoperative diagnosis and management of PAS.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy design\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective observational study included patients diagnosed with placenta praevia who delivered at Okayama University Hospital (Okayama, Japan) between January 2017 and June 2024. Clinical data were obtained from electronic medical records, conference documentation, operative notes, and surgical video recordings. The study was approved by the Ethics Committee of Okayama University Hospital (Approval No.: 2409-047), and relevant information was disclosed to eligible patients via an opt-out approach.\u003c/p\u003e\n\u003cp\u003eAmong the 3,080 deliveries that occurred at our institution during the study period, we included patients who met the following criteria: singleton pregnancy, age \u0026ge;18 years, diagnosis of placenta praevia, delivery by caesarean section, and availability of intraoperative TVUS data for blood flow assessment. Medical records, conference materials, surgical reports, and intraoperative videos were reviewed for all eligible patients. Exclusion criteria were multiple pregnancies, caesarean deliveries performed entirely under general anaesthesia from the outset of the procedure, absence of intraoperative TVUS blood flow recordings or documentation, stillbirths, marginal placenta praevia, and low-lying placenta.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePreoperative Risk Assessment for PAS in Placenta Praevia\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePlacenta praevia was defined as a condition in which the placenta completely or partially covered the internal cervical os\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[17]. In cases diagnosed with placenta praevia via TVUS prior to 32 weeks of gestation during routine antenatal check-ups, further detailed assessment of placental adherence was undertaken at approximately 33 weeks using both MRI and TVUS. MRI findings suggestive of abnormal placental adherence were interpreted by certified radiologists and included the presence of dark intraplacental bands on T2-weighted images, heterogeneous placental signal intensity, indistinct borders between the placenta and myometrium, myometrial thinning or interruption, and focal uterine bulging\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[1,18-20]. Additionally, based on the method proposed by Ishibashi et al. for predicting PAS using the ratio of cervical varicosity depth to placental thickness, sagittal T2-weighted images including the internal cervical os were used\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[4, 5, 21]. To quantify cervical varicosities, we calculated the A/B ratio\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[4], where \u0026ldquo;A\u0026rdquo; represented the shortest distance from the most posterior cervical varicosity to the decidual surface of the placenta, and \u0026ldquo;B\u0026rdquo; represented the shortest distance from the same varicosity to the amniotic side of the placenta (Figure 1). In cases where the multidisciplinary team assessed a high risk of PAS and considered hysterectomy likely, preoperative preparations such as ureteric stent placement or temporary balloon occlusion of the internal iliac arteries were carried out immediately prior to surgery. In all such cases, 300\u0026ndash;900 mL of autologous blood was prepared in advance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePrimary Outcome Measurement (Intraoperative Transvaginal Ultrasound Assessment of Cervical Blood Flow)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary outcome of this study was the intraoperative evaluation of blood flow using TVUS. Patients were placed in the lithotomy position, with a dedicated ultrasound examiner positioned between the legs. A transvaginal probe (5\u0026ndash;9 MHz; Canon Aplio i800, Tokyo, Japan) was used. In the sagittal plane on greyscale imaging, the target imaging plane was defined as the plane showing the cervical line extending from the external to the internal cervical os. Within this plane, colour flow signals corresponding to cervical varicosities located between the placenta and myometrium were assessed (Figure 2). Colour Doppler mode was employed to detect low-velocity blood flow (2.0\u0026ndash;12.0 cm/s), using the preoperative colour flow signal as a reference.\u003c/p\u003e\n\u003cp\u003eIntraoperatively, continuous observation of cervical varicosities was conducted from fetal delivery until placental delivery. The duration of detectable blood flow\u0026mdash;referred to as the blood flow persistence time\u0026mdash;was defined as the interval from fetal delivery to the disappearance of the colour flow signal (velocity \u0026le; 2.0 cm/s), based on the preoperative reference. A velocity threshold of \u0026le; 2.0 cm/s was selected because, at this level, colour flow signals typically become undetectable in Colour Doppler mode due to technical limitations in visualising very low-velocity flow. Thus, this value serves as a practical indicator of blood flow cessation in patients with cervical varicosities. The blood flow persistence time was recorded in minutes. Each case was retrospectively reviewed using operative video footage and surgical records. Two obstetricians specialising in perinatal medicine independently measured the blood flow persistence time. Interobserver agreement was assessed using the kappa coefficient. In cases of discrepancy between observers, the mean of the two measurements was used. For cases in which blood flow persisted beyond 40 minutes, the persistence time was uniformly recorded as 40 minutes. Two representative cases demonstrating the duration of blood flow within cervical varicosities\u0026mdash;one diagnosed with PAS and one without\u0026mdash;are presented as supplementary videos in Videoclip S1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eDiagnosis of PAS\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe presence or absence of PAS was assessed based on clinical and pathological findings, in accordance with the International Federation of Gynaecology and Obstetrics (FIGO) classification system\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[22]. PAS was defined as grade 1 (placenta accreta), grade 2 (placenta increta), or grade 3 (placenta percreta: 3a, 3b, and 3c). The diagnosis was made based on intraoperative findings\u0026mdash;such as difficulty in placental removal\u0026mdash;documented in surgical records, and/or histopathological confirmation of PAS. All pathological evaluations were performed by certified pathologists.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMajor Adverse Outcome\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary adverse outcome assessed in this study was peripartum hysterectomy. No maternal deaths related to placenta praevia occurred during the study period.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eOther Outcomes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAdditional clinical data collected included maternal age at delivery, parity, mode of conception, pregnancy-related complications, gestational age at delivery, medical and surgical history (including prior PAS, uterine surgeries, dilatation and curettage, and endometriosis), smoking history, additional interventions for haemostasis, and estimated intraoperative blood loss.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical Analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe required sample size was estimated through power analysis to evaluate diagnostic accuracy. Assuming an expected area under the curve (AUC) of 0.80, a null hypothesis AUC of 0.60, a significance level of 0.05, and a statistical power of 90%, the minimum number of required cases was calculated to be 33, based on an assumed 1:2 ratio of PAS-positive to PAS-negative cases.\u003c/p\u003e\n\u003cp\u003eReceiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of intraoperative cervical varicosity blood flow persistence time in predicting PAS in patients with placenta praevia. Blood flow persistence times beginning at 6 minutes were assessed at one-minute intervals to evaluate the sensitivity, specificity, and predictive values associated with each threshold. The optimal cut-off value was determined using the Youden index, and the corresponding sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. For the multivariable analysis, logistic regression was conducted using blood flow persistence time, history of caesarean section, mode of conception, and preoperative PAS prediction (MRI A/B ratio) as covariates. There were no missing data regarding patient demographic characteristics or primary outcome measures. However, a small number of cases had missing values for the MRI-based preoperative PAS assessment. Given the non-essential nature of these variables in the primary analysis and the relatively small proportion of missing data, no imputation was performed. Cases with missing MRI data were excluded from analyses involving MRI findings. All statistical analyses were conducted using SAS V.9.4 TS1M8 (SAS Institute, Cary, NC, USA), while sensitivity analyses and figure generation were performed using Python (v3.10.12).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSensitivity Analyses\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTwo sensitivity analyses were conducted to evaluate the robustness of our findings. In the first analysis, cases of increta and percreta were excluded in order to assess diagnostic accuracy specifically for placenta accreta. ROC analysis was repeated using only accreta cases as the positive group. In the second analysis, the primary analysis was repeated after including cases that had initially been excluded due to general anaesthesia or marginal placenta praevia, to examine the impact of these exclusion criteria on diagnostic performance.\u003c/p\u003e"},{"header":"Result","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy Population and Baseline Characteristics\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong the patients who underwent caesarean section for placenta praevia, 76 cases were initially identified. After excluding 24 patients based on predefined criteria, 52 were included in the final analysis (Figure 3). Table 1 summarises the maternal characteristics and clinical outcomes stratified by the presence or absence of PAS. The mean maternal age across all cases was 34.45 \u0026plusmn; 4.97 years, and 24 of the 52 patients (46.2%) were nulliparous. PAS was diagnosed in 20 of the 52 patients (38.5%). Among those with PAS, a history of prior caesarean delivery was observed in 7 of 20 cases (35.0%), and a history of endometrial curettage was reported in 8 of 20 patients (40.0%). Regarding the mode of conception, in vitro fertilisation (IVF) was more frequent in the PAS group (8 of 20; 40.0%) than in the non-PAS group (6 of 32; 18.8%), indicating a tendency towards higher prevalence in the PAS group. MRI A/B ratios were lower in the PAS group (0.26 \u0026plusmn; 0.13) than in the non-PAS group (0.38 \u0026plusmn; 0.13). The mean duration of cervical varicosity blood flow, measured from fetal delivery, was 11.09 \u0026plusmn; 11.64 minutes across all cases. In the PAS group, the duration was significantly longer, with a mean of 20.20 \u0026plusmn; 14.31 minutes, compared to 5.69 \u0026plusmn; 2.46 minutes in the non-PAS group. The interobserver agreement for the assessment of blood flow duration was substantial, with a kappa coefficient of 0.67. Hysterectomy was performed in 7 of the 52 cases (13.5%), all of which occurred in the PAS group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eDiagnostic Accuracy of Blood Flow Persistence Time for PAS\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 4 presents the ROC curve assessing the diagnostic performance of cervical varicosity flow duration for the diagnosis of PAS. The AUC was 0.94, and the optimal cut-off was 7 minutes. Table 2 summarises the diagnostic performance metrics for cut-off values ranging from 6 to 15 minutes. At the 7-minute threshold, sensitivity was 1.00, specificity was 0.72, the PPV was 0.69, and the NPV was 1.00. At 11 minutes, sensitivity decreased to 0.55, specificity increased to 0.97, PPV was 0.92, and NPV was 0.78. A blood flow persistence time of \u0026ge;11 minutes was highly predictive of PAS. Furthermore, a duration exceeding 14 minutes was observed in only a limited number of PAS cases but demonstrated a PPV of 1.00. The ROC curve in Figure 5 reflects the results of the multivariable analysis, which included cervical vascular flow duration alongside clinical and imaging predictors, demonstrating high diagnostic accuracy for PAS. The AUC following multivariate analysis was 0.95. The optimal cut-off value for blood flow duration was 8 minutes, with a sensitivity of 0.95 and specificity of 0.91.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePredictive Value for Hysterectomy\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe diagnostic performance of blood flow persistence time for predicting peripartum hysterectomy was evaluated, and the results are summarised in Table 3. At a cut-off of 7 minutes, the sensitivity was 1.00, specificity was 0.51, the PPV was 0.24, and the NPV was 1.00. Specificity improved to 0.93 at a cut-off of 13 minutes. When the threshold was set at \u0026ge;15 minutes, sensitivity remained at 1.00, specificity increased to 0.96, PPV was 0.78, and NPV remained at 1.00.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSensitivity analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor cases restricted to placenta accreta, the AUC was 0.92, with the optimal cut-off point being 7 minutes; a flow duration exceeding 14 minutes yielded a PPV of 1.00 (Table 4, Figure 6). When cases involving general anaesthesia and marginal placenta praevia were included, the AUC remained high at 0.95, with an optimal cut-off of 8 minutes, consistent with the main analysis (Table 5, Figure7).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study evaluated the clinical utility of real-time TVUS as an intraoperative diagnostic aid for PAS, focusing on the assessment of blood flow within cervical varicosities during caesarean section for placenta praevia. A blood flow duration of less than 7 minutes was consistently associated with the absence of PAS, thereby supporting standard placental management with confidence. In contrast, a duration of \u0026ge;11 minutes demonstrated a strong association with PAS (PPV = 0.92), and all cases with flow lasting \u0026ge;14 minutes fulfilled the FIGO diagnostic criteria for PAS (PPV = 1.00). These thresholds provide an objective and actionable parameter to guide intraoperative decision-making. When blood flow persists beyond 7 minutes, a brief pause and team reassessment may facilitate timely preparation for escalated interventions, such as hysterectomy or massive transfusion, while minimising the risk of hasty or forceful placental separation.\u003c/p\u003e\n\u003cp\u003eIn the absence of PAS, placental separation occurs along the decidual interface, leading to the physiological collapse of maternal\u0026ndash;fetal vascular shunts, including spiral artery flow. This results in the rapid cessation of blood flow within the uterine wall and cervical vascular layers [23-25]. In contrast, the physiological rationale for persistent flow in PAS aligns with established pathophysiological mechanisms. In PAS, failure of normal decidualisation permits direct invasion of trophoblasts into the myometrium, serosa, or adjacent organs, resulting in the formation of abnormal arteriovenous communications between maternal and placental circulations\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[25,26]. These pathological shunts often remain patent even after attempts at placental separation, allowing for sustained perfusion.\u003c/p\u003e\n\u003cp\u003eParticularly in the lower uterine segment and cervix\u0026mdash;where collateral venous pathways such as the paracervical and parametrial plexuses are often well developed\u0026mdash;blood flow may be maintained through both placental and extraplacental vascular supplies. Our intraoperative observations of persistent low-velocity blood flow likely reflect these underlying structural and haemodynamic abnormalities in real time, and may serve as a non-invasive physiological surrogate for pathological invasion in PAS. In this context, the persistence time of cervical varicosities represents a reproducible, physiological, and temporally responsive marker that can be assessed dynamically and non-invasively. Unlike static imaging features such as placental lacunae or myometrial thinning\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[7,18], flow duration permits continuous monitoring throughout the procedure, providing valuable intraoperative feedback as the surgical situation evolves. This is particularly advantageous when preoperative imaging findings are equivocal, inconsistent, or unavailable.\u003c/p\u003e\n\u003cp\u003eImportantly, the present study highlights the inherent limitations of relying exclusively on preoperative imaging for the diagnosis of PAS. Conventional ultrasonographic indicators\u0026mdash;such as the presence of multiple placental lacunae, discontinuity of the bladder wall, and attenuation or absence of the hypoechoic myometrial zone\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[1,3,6,7]\u0026mdash;as well as more recent MRI features\u0026mdash;including dark intraplacental bands on T2-weighted sequences, focal bulging of the uterine contour, and disruption of the uterine\u0026ndash;placental interface\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[2,7]\u0026mdash;have improved diagnostic accuracy. However, these findings are not universally present in all affected cases. Moreover, interobserver variability and institutional differences in diagnostic experience may undermine the consistency of preoperative assessments. Such variability in risk stratification may contribute to suboptimal intraoperative management, including unnecessary uterine manipulation, delayed decisions regarding hysterectomy, or an increased risk of severe haemorrhage\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[12].\u003c/p\u003e\n\u003cp\u003eSeveral factors are known to contribute to adverse outcomes in cases of unexpected PAS, including delayed recognition, unplanned responses to haemorrhage, the use of inappropriate surgical techniques (e.g., forceful placental removal), poor intra-team communication, and insufficient preparation\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[13,27]. Intraoperative uncertainty often gives rise to confusion and panic, increasing the likelihood of maternal morbidity. An objective marker such as cervical blood flow duration could help bridge this gap by aligning team understanding, reducing cognitive bias, and supporting shared decision-making in real time. Notably, real-time intraoperative metrics are rare in obstetric surgery, and the introduction of a practical and reproducible marker represents a meaningful contribution to the field.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStrengths and Limitations\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study is the first to evaluate blood flow duration as an intraoperative predictor of PAS. By quantifying a physiological parameter using the widely available TVUS, we propose a practical tool that may support intraoperative decision-making and enhance surgical safety. However, it is important to acknowledge that the recommended intraoperative responses based on specific blood flow duration thresholds were developed within the context of our institution\u0026rsquo;s patient population and surgical protocols. Therefore, these strategies may not be generalisable to all clinical settings. To support potential adaptation in other institutions, detailed decision-making pathways and intraoperative management algorithms are provided in Table 6.\u003c/p\u003e\n\u003cp\u003eNonetheless, this study has several limitations. First, it was a retrospective, single-centre study, which may limit the generalisability of the findings. Second, although efforts were made to standardise the measurement of flow duration, the final classification relied on consensus between two experienced obstetricians, introducing a degree of subjectivity. Moreover, surgical outcomes such as hysterectomy were influenced not only by blood loss and placental adherence but also by surgeon experience, urgency of the case, and patient comorbidities. These confounding factors may affect the strength of the association between flow duration and clinical outcomes.\u003c/p\u003e\n\u003cp\u003eFuture prospective, multicentre studies are warranted to validate these findings and establish standardised thresholds for clinical use. In addition, efforts to automate and quantify flow duration using software or integrated Doppler imaging systems may further enhance reproducibility. Ultimately, the integration of cervical varicosity blood flow monitoring into obstetric surgical protocols may provide a simple, non-invasive, and effective strategy to improve maternal safety and refine intraoperative diagnosis and management of PAS.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe intraoperative assessment of blood flow duration within cervical varicosities using TVUS offers a reproducible and physiologically meaningful marker suggestive of PAS in patients with placenta praevia. The cessation of low-velocity flow within 7 minutes following fetal delivery reliably excludes PAS, whereas persistent flow of 14 minutes or more is highly suggestive of its presence.\u003c/p\u003e\n\u003cp\u003eIncorporating this objective parameter into intraoperative decision-making may facilitate risk stratification, optimise surgical planning, and ultimately improve maternal safety during caesarean delivery for placenta praevia.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAUC \u0026ndash; Area Under the Curve\u003c/p\u003e\n\u003cp\u003eFIGO \u0026ndash; International Federation of Gynaecology and Obstetrics\u003c/p\u003e\n\u003cp\u003eIVF \u0026ndash; In Vitro Fertilisation\u003c/p\u003e\n\u003cp\u003eMRI \u0026ndash; Magnetic Resonance Imaging\u003c/p\u003e\n\u003cp\u003eNPV \u0026ndash; Negative Predictive Value\u003c/p\u003e\n\u003cp\u003ePAS \u0026ndash; Placenta Accreta Spectrum\u003c/p\u003e\n\u003cp\u003ePPV \u0026ndash; Positive Predictive Value\u003c/p\u003e\n\u003cp\u003eROC \u0026ndash; Receiver Operating Characteristic\u003c/p\u003e\n\u003cp\u003eTVUS \u0026ndash; Transvaginal Ultrasonography\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003cbr\u003e\u003c/strong\u003eThis study was approved by the Ethics Committee of Okayama University Hospital (Approval No.: 2409-047). In accordance with institutional policy, information regarding the study was disclosed to eligible patients via an opt-out approach, and consent was obtained accordingly.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003cbr\u003e\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors confirm their individual contributions to the study as follows:\u003c/p\u003e\n\u003cp\u003eTM: Conceptualization, Investigation, Data Curation, Visualization, Writing Formal Analysis, Writing \u0026ndash; Original Draft\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSS: Investigation, Data Curation, Supervision, Resources\u003c/p\u003e\n\u003cp\u003eAS: Investigation, Data Curation, Validation\u003c/p\u003e\n\u003cp\u003eHO: Data Curation, Statistical support, Investigation\u003c/p\u003e\n\u003cp\u003eKH: Supervision, Data Curation, Validation, Investigation \u0026ndash; Review\u003c/p\u003e\n\u003cp\u003eJM: Conceptualization, Methodology, Statistical advice \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to express our sincere gratitude to all healthcare professionals involved in the multidisciplinary management of placenta praevia surgeries. In particular, we extend our appreciation to the midwives, nurses, anaesthetists, radiologists, clinical engineers, and paediatricians at Okayama University Hospital for their dedicated support and collaboration. Their expertise and commitment have been invaluable in ensuring the safety and quality of peripartum care.\u003c/p\u003e\n\u003cp\u003eWe also thank Chiaki Kuriyama, Hikari Nakato, Kazumasa Kato, Sakurako Mishima, Akiko Ohira, Stoe Kirino, Eriko Eto, and Hisashi Masuyama for their valuable contributions to clinical practice and academic guidance.\u003c/p\u003e\n\u003cp\u003eWe gratefully acknowledge the financial support provided by Okayama University for the open access publication of this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDetails of Ethics Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of Okayama University Hospital (Approval No.:\u003cem\u003e2409-047\u003c/em\u003e). The requirement for written informed consent was waived due to the retrospective nature of the study, and information about the study was disclosed publicly in accordance with the opt-out policy approved by the ethics committee. The study was conducted in accordance with the principles of the Declaration of Helsinki. No clinical trial registration was required, as this was a retrospective observational study. No animals were involved in this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eMaurea S, Verde F, Romeo V, Stanzione A, Mainenti PP, Raia G, et al. Prediction of placenta accreta spectrum in patients with placenta previa using a clinical, US and MRI combined model: A retrospective study with external validation. Eur J Radiol. 2023 Nov;168:111116.\u003c/li\u003e\n \u003cli\u003eBalcacer P, Pahade J, Spektor M, Staib L, Copel JA, McCarthy S. Magnetic Resonance Imaging and Sonography in the Diagnosis of Placental Invasion. J Ultrasound Med. 2016 Jul;35(7):1445-56.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eHasegawa K, Ikenoue S, Tanaka Y, Oishi M, Endo T, Sato Y, Ishii R, Kasuga Y, Ochiai D, Tanaka M. Ultrasonographic Prediction of Placental Invasion in Placenta Previa by Placenta Accreta Index. J Clin Med. 2023 Jan 31;12(3):1090.\u003c/li\u003e\n \u003cli\u003eIshibashi H, Miyamoto M, Shinmoto H, Soga S, Matsuura H, Kakimoto S, Iwahashi H, Sakamoto T, Hada T, Suzuki R, Takano M. The use of magnetic resonance imaging to predict placenta previa with placenta accreta spectrum. Acta Obstet Gynecol Scand. 2020 Dec;99(12):1657-1665.\u003c/li\u003e\n \u003cli\u003eIshibashi H, Miyamoto M, Shinmoto H, Soga S, Iwahashi H, Kakimoto S, Matsuura H, Sakamoto T, Hada T, Suzuki R, Takano M. Applicability of ultrasonography for detection of marginal sinus placenta previa. Medicine (Baltimore). 2021 Jan 8;100(1):e24253.\u003c/li\u003e\n \u003cli\u003eJauniaux E, Bhide A. Prenatal ultrasound diagnosis and outcome of\u0026nbsp;placenta previa accreta after cesarean delivery: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017 Jul;217(1):27-36.\u003c/li\u003e\n \u003cli\u003eZhang J, Li H, Feng D, Wu J, Wang Z, Feng F. Ultrasound scoring system for prenatal diagnosis of placenta accreta spectrum. BMC Pregnancy Childbirth. 2023 Aug 7;23(1):569.\u003c/li\u003e\n \u003cli\u003eSkupski DW, Duzyj CM, Scholl J, Perez-Delboy A, Ruhstaller K, Plante LA, Hart LA, Palomares KTS, Ajemian B, Rosen T, Kinzler WL, Ananth C; Perinatal Research Consortium. Evaluation of classic and novel ultrasound signs of placenta accreta spectrum. Ultrasound Obstet Gynecol. 2022 Apr;59(4):465-473.\u003c/li\u003e\n \u003cli\u003eEinerson BD, Gilner JB, Zuckerwise LC. Placenta Accreta Spectrum. Obstet Gynecol. 2023 Jul 1;142(1):31-50.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSilver RM, Branch DW. Placenta Accreta Spectrum. N Engl J Med. 2018 Apr 19;378(16):1529-1536.\u003c/li\u003e\n \u003cli\u003eMain EK, Goffman D, Scavone BM, Low LK, Bingham D, Fontaine PL, Gorlin JB, Lagrew DC, Levy BS. National Partnership for Maternal Safety: consensus bundle on obstetric hemorrhage. Anesth Analg. 2015 Jul;121(1):142-148.\u003c/li\u003e\n \u003cli\u003eSilver RM, Fox KA, Barton JR, Abuhamad AZ, Simhan H, Huls CK, Belfort MA, Wright JD. Center of excellence for placenta accreta. Am J Obstet Gynecol. 2015 May;212(5):561-8.\u003c/li\u003e\n \u003cli\u003eShamshirsaz AA, Fox KA, Salmanian B, Diaz-Arrastia CR, Lee W, Baker BW, et al. Maternal morbidity in patients with morbidly adherent placenta treated with and without a standardized multidisciplinary approach. Am J Obstet Gynecol. 2015 Feb;212(2):218.e1-9.\u003c/li\u003e\n \u003cli\u003eJauniaux E, Alfirevic Z, Bhide AG, Belfort MA, Burton GJ, Collins SL, et al. BJOG. 2019 Jan;126(1):e1-e48.\u003c/li\u003e\n \u003cli\u003eAmerican College of Obstetricians and Gynecologists; Society for Maternal-Fetal Medicine. Obstetric Care Consensus No. 7: Placenta Accreta Spectrum. Obstet Gynecol. 2018 Dec;132(6):e259-e275.\u003c/li\u003e\n \u003cli\u003eElmaraghy AM, Taha Fayed S, Abd ElHamid Ali M, Ali Hassanien M, Mohamed Mamdouh A. Diagnostic Accuracy of Placental Thickness in Lower Uterine Segment Measured by Ultrasound in Prediction of Placenta Accreta Spectrum in Patients with Placenta Previa. A Diagnostic Test Accuracy Study. Int J Womens Health. 2023 Feb 16;15:311-320.\u003c/li\u003e\n \u003cli\u003eSentilhes L, Kayem G, Silver RM. Conservative Management of Placenta Accreta Spectrum. Clin Obstet Gynecol. 2018 Dec;61(4):783-794.\u003c/li\u003e\n \u003cli\u003eKapoor H, Hanaoka M, Dawkins A, Khurana A. Review of MRI imaging for placenta accreta spectrum: Pathophysiologic insights, imaging signs, and recent developments. Placenta. 2021 Jan 15;104:31-39.\u003c/li\u003e\n \u003cli\u003eRahaim NS, Whitby EH. The MRI features of placental adhesion disorder and their diagnostic significance: systematic review. Clin Radiol. 2015 Sep;70(9):917-25.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePain FA, Dohan A, Grange G, Marcellin L, Uzan-Augui J, Goffinet F, et al. Percreta score to differentiate between placenta accreta and placenta percreta with ultrasound and MR imaging. Acta Obstet Gynecol Scand. 2022 Oct;101(10):1135-1145.\u003c/li\u003e\n \u003cli\u003eIshibashi H, Miyamoto M, Shinnmoto H, Murakami W, Soyama H, Nakatsuka M, Natsuyama T, Yoshida M, Takano M, Furuya K. Cervical varicosities may predict placenta accreta in posterior placenta previa: a magnetic resonance imaging study. Arch Gynecol Obstet. 2017 Oct;296(4):731-736.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eJauniaux E, Ayres-de-Campos D, Langhoff-Roos J, Fox KA, Collins S; FIGO Placenta Accreta Diagnosis and Management Expert Consensus Panel. FIGO classification for the clinical diagnosis of placenta accreta spectrum disorders. Int J Gynaecol Obstet. 2019 Jul;146(1):20-24.\u003c/li\u003e\n \u003cli\u003eHerman A, Zimerman A, Arieli S, Tovbin Y, Bezer M, Bukovsky I, et al. Down-up sequential separation of the placenta. Ultrasound Obstet Gynecol. 2002 Mar;19(3):278-81.\u003c/li\u003e\n \u003cli\u003eGusella A, Martignoni G, Giacometti C. Behind the Curtain of Abnormal Placentation in Pre-Eclampsia: From Molecular Mechanisms to Histological Hallmarks. Int J Mol Sci. 2024 Jul 18;25(14):7886.\u003c/li\u003e\n \u003cli\u003eKrapp M, Baschat AA, Hankeln M, Gembruch U. Gray scale and color Doppler sonography in the third stage of labor for early detection of failed placental separation. Ultrasound Obstet Gynecol. 2000 Feb;15(2):138-42.\u003c/li\u003e\n \u003cli\u003eJauniaux E, Collins S, Burton GJ. Placenta accreta spectrum: pathophysiology and\u0026nbsp;evidence-based anatomy for prenatal ultrasound imaging. Am J Obstet Gynecol. 2018 Jan;218(1):75-87.\u003c/li\u003e\n \u003cli\u003eErfani H, Fox KA, Clark SL, Rac M, Rocky Hui SK, Rezaei A, et al. Maternal outcomes in unexpected placenta accreta spectrum disorders: single-center experience with a multidisciplinary team. Am J Obstet Gynecol. 2019 Oct;221(4):337.e1-337.e5.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" valign=\"top\" style=\"width: 648px;\"\u003e\n \u003cp\u003eTable 1. Comparison of clinical characteristics according to the presence of placenta accreta spectrum\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 264px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003ePAS (+)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp\u003ePAS (-)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 264px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003en=20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp\u003en=32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eAge, mean years, SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e35.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e33.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e4.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eParity, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003ePrimiparous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eMultiparous\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eGynecological history, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eCesarean section\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003ePlacenta previa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eMyomectomy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eEndometrial curettage\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eEndometriosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eConception, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eSpontaneous conception\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eIntrauterine insemination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eIn vitro fertilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eCourse of pregnancy, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eSentinel bleeding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eGestational diabetes mellitus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003ePregnancy with uterine fibroids\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003ePlacental location, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eAnteriorly dominant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003ePosteriorly dominant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003ePreoperative adhesion assessment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eMRI-suspected adhesions*, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eMRI-based A/B score of cervical varicosities\u0026dagger;, mean score, SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eIntraoperative findings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eBleeding, ml, SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2523\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2037\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e1594\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e711\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eTime to disappearance of blood flow within cervical varicosities, mean, SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e20.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e14.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e2.46\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003ePlacental delivery time, mean min, SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e23.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e22.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e8.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e5.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eIntraoperative interventions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eManual placental removal, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eBipolar vessel sealing device, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e15.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eHemostatic suturing, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e37.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eCompression suture, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eIntrauterine balloon tamponade, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e37.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003eOutcome\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eHysterectomy, n, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 293px;\"\u003e\n \u003cp\u003ePlacenta accreta spectrum classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eFIGO Ⅰ(accreta)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eFIGO Ⅱ(inccreta)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 15px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 278px;\"\u003e\n \u003cp\u003eFIGO Ⅲ(percreta)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 91px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 82px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" valign=\"top\" style=\"width: 648px;\"\u003e\n \u003cp\u003eAbbreviation; FIGO, International Federation of Gynecology and Obstetrics; MRI, magnetic resonance image; PAS, placenta accreta spectrum; SD, standard deviation;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" valign=\"top\" style=\"width: 648px;\"\u003e\n \u003cp\u003e* In the MRI examination, the presence of any one of the following four indicators suggestive of placenta accreta spectrum was considered to indicate a risk of placental adhesion:dark T2-weighted intraplacental bands, heterogeneous signals in the placenta, myometrial thinning or interruption, and focal uterine bulging.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" valign=\"top\" style=\"width: 648px;\"\u003e\n \u003cp\u003e\u0026dagger; Cervical varicosities were evaluated using T2-weighted sagittal images including the internal cervical os. The minimum distance from the most dorsal cervical varicosities to (A) the decidual (placental) side and (B) the amniotic side was measured and used for scoring.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003eTable 2. Cut-off levels of blood flow persistence time for the occurrence of placenta accreta spectrum.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003ecutoff value for blood flow persistence time* (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSensitivity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSpecificity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003ePositive predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eNegative predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003e*It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003eTable 3. Cutoff levels of blood flow persistence time for the occurrence of total abdominal hysterectomy.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003eCutoff value for blood flow persistence time* (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSensitivity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSpecificity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003ePositive predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eNegative predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003e*It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003eTable 4. Sensitivity analysis of blood flow signal duration cutoff levels for diagnosing placenta accreta, excluding placenta increta and percreta cases.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003eCutoff value for blood flow duration* (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSensitivity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSpecificity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003ePositive predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eNegative predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003e*It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" class=\"fr-table-selection-hover\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003eTable 5. Sensitivity Analysis of Blood Flow Signal Cutoff Levels After Modification of Eligibility Criteria*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003eCut-off value for blood flow duration\u0026dagger; (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSensitivity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eSpecificity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003ePositive predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eNegative predictive value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 166px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003e*The main analysis was repeated after including cases that were initially excluded due to general anesthesia or marginal placenta previa, in order to examine the impact of these exclusion criteria on diagnostic performance.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003e\u0026dagger; It defined as the time from fetal delivery to the disappearance of the color flow signal based on the preoperative reference signal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 649px;\"\u003e\n \u003cp\u003eTable 6. Recommended intraoperative management steps based on cervical blood flow persistence time during cesarean section for placenta previa.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eFlow duration range\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eClinical interpretation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 328px;\"\u003e\n \u003cp\u003eRecommended intraoperative actions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eNotes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e\u0026lt; 7 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eLow likelihood of PAS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 328px;\"\u003e\n \u003cp\u003eProceed with standard surgical procedure. Avoid unnecessary placental separation to ensure safety.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eHigh negative predictive value (NPV).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e7\u0026ndash;11 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eIntermediate zone; moderate risk of PAS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 328px;\"\u003e\n \u003cp\u003eInitiate intraoperative team huddle. Reassess surgical field. Prepare for hemostasis, blood transfusion, and consider potential need for TAH. Communicate with anesthesia and transfusion teams.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eSurgical reassessment and team coordination needed.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e11\u0026ndash;14 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003eHigh likelihood of PAS (PPV \u0026asymp; 92%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 328px;\"\u003e\n \u003cp\u003ePromptly notify anesthesiology and transfusion teams. Begin transfusion and prepare for surgical hemostasis. Reconfirm role assignments among surgical team.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eImmediate action is critical.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e\u0026ge;14 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 152px;\"\u003e\n \u003cp\u003ePAS almost certain (PPV = 100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 328px;\"\u003e\n \u003cp\u003ePrepare for TAH or staged surgery. Consider operator replacement and request experienced surgical backup. Ensure rapid team communication and coordination of intraoperative management.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eAll cases with \u0026ge;14 min was confirmed PAS.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"placenta accreta spectrum, placenta praevia, caesarean section, intraoperative ultrasonography, cervical varicosity, transvaginal ultrasonography, multidisciplinary team, hysterectomy","lastPublishedDoi":"10.21203/rs.3.rs-6938564/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6938564/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo assess the utility of intraoperative transvaginal ultrasonography (TVUS) in evaluating the duration of blood flow in cervical varicosities as a real-time diagnostic marker for placenta accreta spectrum (PAS) in placenta praevia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis single-centre historical cohort study included patients with placenta praevia who underwent caesarean section with intraoperative TVUS. The primary outcome was blood flow persistence time, defined as the interval from fetal delivery to disappearance of low-velocity (≤ 2.0 cm/s) colour Doppler signals in cervical varicosities—dilated venous structures in the cervical stroma commonly observed in abnormal placentation. TVUS was performed in the sagittal plane including the internal cervical os. Flow persistence time was retrospectively measured from surgical video recordings and was independently assessed by two obstetricians. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of flow persistence time for predicting PAS. The area under ROC curve (AUC) was calculated to assess discriminative ability. Optimal cutoff values were determined using sensitivity, specificity, and predictive values. Multivariate regression identified independent predictors of PAS, and model performance was evaluated using AUC.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong the 52 included cases, PAS was diagnosed in 20 (38.5%). Blood flow persistence time was longer in PAS cases (20.20 ± 14.31 min) than in non-PAS cases (5.69 ± 2.46 min). A cutoff of 7 min yielded a sensitivity of 1.00 and specificity of 0.72 for PAS diagnosis (AUC = 0.94), reliably ruling out PAS when flow ceased within this time. Conversely, a duration of ≥14 min had a positive predictive value of 1.00, strongly indicating the presence of PAS. Multivariable analysis confirmed that flow duration was an independent predictor of PAS (AUC = 0.95). For predicting hysterectomy, a threshold of ≥14 min achieved a specificity of 0.96 and a negative predictive value of 1.00.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIntraoperative measurement of cervical varicosity blood flow duration via TVUS offers a reproducible, real-time physiological marker for PAS. A flow duration under 7 min reliably excludes PAS, while durations exceeding 14 min strongly suggest its presence. Incorporating this marker into intraoperative decision-making may enhance preparedness and maternal safety during caesarean delivery for placenta praevia.\u003c/p\u003e","manuscriptTitle":"Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: a retrospective observational study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-02 06:54:35","doi":"10.21203/rs.3.rs-6938564/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"07bb26c4-2dae-409e-b130-7288f989765b","owner":[],"postedDate":"July 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-25T10:23:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-02 06:54:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6938564","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6938564","identity":"rs-6938564","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}