Influence of antepartum hemorrhage on placenta previa: A multi-center, retrospective cohort study

Influence of antepartum hemorrhage on placenta previa: A multi-center, retrospective cohort 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 Influence of antepartum hemorrhage on placenta previa: A multi-center, retrospective cohort study Wenjie Qing, Linda Li, Alyssia Venna, Jie Zhou This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-61700/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Jan, 2021 Read the published version in Clinical and Experimental Obstetrics & Gynecology → Version 1 posted You are reading this latest preprint version Abstract BACKGROUND Placenta previa can be a serious, life-threatening obstetric complication that causes painless but potentially catastrophic bleeding. It is unclear as to whether the frequency of antepartum hemorrhage (APH) relative to the specific gestational week in placenta previa will lead to negative perinatal outcomes. The purpose of the present study was to determine the relationship between APH and gestational week number, and to ascertain the different perinatal outcomes in women with placenta previa. METHODS This was a multi-center, retrospective study in which we enrolled all women with placenta previa between October of 2015 and September of 2018. Patients with placenta previa were divided into two groups: women with APH and women without APH. RESULTS A total of 247 patients were included in this study: 121 women with APH and 126 women without. The incidence of APH was 49.0% (121/247). The mean bleeding frequency was 2.2 ± 1.3 (mean ± SD), with the majority having experienced a one-time bleeding episode (36.4%, 44/121), followed by 26.4% with 2 episodes (32/121), and 23.1% with 3 (28/121). The APH was distinct in every gestational-week category, with bleeding occurring at 31.4 ± 3.3 weeks, ranging from 24 to 37 gestational weeks. The incidence of bleeding varied from 2.6–14.6%, with the highest incidence at 32 gestational weeks. Patients categorized as having complete placental coverage included a greater number of women experiencing bleeding than women who did not bleed (72.9% vs 47.4%, P < 0.001), indicating that a complete placenta was an independent risk factor for APH (odds rations [OR], 4.17; 95% confidence interval [CI], 1.805–9.634). In addition, although APH did not augment the rates of hysterectomy (6.6% vs 7.1%, P = 0.869), it was associated with critical neonatal outcomes that included lower weight, lower Apgar score at 1 minute, preterm age, and more frequent neonatal intensive care unit admissions (P < 0.05). CONCLUSIONS The gestational week and frequency of each APH varied in patients with placenta previa and might result in an increase in adverse maternal and neonatal outcomes. The 32nd gestational week appeared to be the most precarious time—exhibiting the highest incidence of bleeding—and we consider complete placenta previa to be an independent risk factor for APH. Maternal & Fetal Medicine Cesarean delivery Placenta previa Antepartum hemorrhage Preterm Perinatal outcome Figures Figure 1 Figure 2 Background: Placenta previa—a condition where the placenta lies directly over the internal os 1 —is a serious obstetric complication that leads to increased maternal and neonatal mortality and morbidity; its incidence is reported to vary between 0.15% and 0.91%. 2 – 6 Clinically, placenta previa presents as recurrent painless vaginal bleeding in the antenatal period and massive hemorrhage during cesarean delivery (CD) and postoperatively. Antepartum hemorrhage (APH) is defined as bleeding from or into the genital tract that occurs from 24 + 0 weeks of pregnancy and prior to the birth of the baby. 7 However, not all patients with placenta previa encounter APH, and some may not experience any bleeding during the entire prenatal period. It is thus currently unclear as to which risk factors contribute to APH or at which gestational week bleeding occurs. To our knowledge, there are no extant studies in the literature that describe the relationship between APH and gestational week. Given the importance yet paucity of the existing literature on this topic, the aims of the current study were to identify the following in placenta previa patients: 1) the relationship between APH and gestational week, 2) risk factors for APH, and 3) whether patients with APH developed more severe adverse perinatal outcomes. This knowledge will help to improve the antenatal management of placenta previa and optimize prophylactic measures to ameliorate outcomes. Methods: The present investigation was a multi-center, retrospective study approved by the Institutional Review Board at Partners Healthcare System (PHS) (Protocol#2019P000028). We collected all patient delivery data between October of 2015 and September of 2018 within PHS; this includes 7 different hospitals, 2 of which are large, tertiary, academic medical centers. The total number of deliveries during this period was 39,945, including 12,884 cesarean deliveries (32.3%) and 27,061 vaginal deliveries (67.7%). We sought patients in the PHS using the indication of placenta previa for “cesarean section” or “cesarean delivery”, and found 259 patients who met this criterion. At our institution, whenever placenta previa was identified by ultrasonography in the second trimester, a follow-up ultrasonographic examination was performed at 32–34 weeks of gestation to evaluate the relationship between the placenta and the cervix. All included cases were consistent with the ultrasonographic image produced before CD. To avoid data bias in maternal and newborn outcomes, we excluded patients with multiple pregnancies (n = 8), stillbirths (n = 1), or delivery at less than 24 weeks of gestational age (n = 3). A total of 247 patients were ultimately included in our study. Demographic data were collected from electronic medical records (EMR) and included maternal age, gravidity, parity, body mass index (BMI), smoking history, in vitro fertilization (IVF) history, prior number of CDs, history of CDs, and duration of the CD interval. The interval duration depicted the interval between the most recent CD and the current delivery. Gestational week was either calculated using the date of the last menstrual period or estimated from the first-trimester ultrasonographic measurements. We obtained placental location and classification from the last ultrasonographic report prior to delivery, and this was validated during CD. The placenta was classified as either complete, incomplete (marginal or partial), or low lying. Placenta accreta was recorded from patient surgical records and confirmed by pathologic diagnosis. We also located maternal and neonatal outcomes in the surgical records as well as in anesthesia and neonatal records. The intraoperative variable of “total blood product” represented the sum total (units) of any blood product administered during the operative period, including packed red blood cells (PRBC), cell salvage, fresh frozen plasma (FFP), platelets, cryoprecipitate, and albumin. We defined postpartum hemorrhage (PPH) as an estimated blood loss (EBL) over 1000 ml. Hemoglobin (HGB) concentration and hematocrit (HCT) percentage during the first trimester, pre-operation, and postoperatively were procured from laboratory results found in the EMR. All vaginal bleeding was recorded in our data, including the number of bleeding episodes and specific gestational week when bleeding occurred. Persistent bleeding was recorded once at the beginning of bleeding; however, if the patient experienced an interval without bleeding for more than 1 week, then the next bleeding was considered a second bleeding incident. Repeated bleeding was recorded several times according to the number of bleeding episodes. All hemorrhages were recorded, including those that occurred during inpatient and outpatient visits; however, bleeding caused by labor was not included. We observed no bleeding caused by neoplasm, infection, trauma, or iatrogenesis in any of our cases. There was also no bleeding due to vasa previa or placental abruption. The amount of bleeding was not included in our data as the majority was not quantified. All included cases met the recommendations and guidelines for data collection and analysis for APH in placenta previa. 8 We conducted our statistical analysis using the Statistical Package for Social Sciences (SPSS) software, version 23.0. Continuous variables are presented as means ± 1 standard deviation (SD) or medians with an inter-quartile range, and we made comparisons between placenta previa with or without APH using the independent-sample t test or non-parametric Mann-Whitney U test depending upon normality of the data distribution. Categorical variables are shown as counts and percentages, and the differences were assessed using Chi-squared analysis; Fisher’s exact-probability test was used when appropriate. A value of P < 0.05 was considered statistically significant. We used logistic regression to study the independent risk factors for APH: the dependent variable was APH, and age, gravidity, parity, BMI, history of CD, number of prior CDs, duration of CD interval, placental location, and placental classification all served as covariates, with P < 0.01 representing a significant difference. Results are reported using odds ratios (OR) and 95% confidence intervals (CI). We used a Kaplan-Meier survival curve to show placenta previa patients with or without APH who remained undelivered at each gestational week. Results: The prevalence of placenta previa in our study was 0.65% (259/39945), and the mean number of gestational weeks at delivery was 36.4 ± 0.5. We identified 247 patients who underwent CD for placenta previa: 17 of these underwent a hysterectomy (6.9%, 17/247), 7 were treated with a uterine balloon (2.8%, 7/247), 3 underwent bilateral uterine artery embolization (1.2%, 3/247), and 7 patients received ureteral stents (2.8%, 7/247). The incidence of APH in placenta previa was 49.0% (121/247). The mean number of bleeding episodes was 2.2 ± 1.3. While most experienced a one-time bleeding episode (36.4%, 44/121), 26.4% had 2 (32/121), 23.1% had 3 (28/121), 9.1% had 4 (11/121), 1.7% had 5 (2/121), 2.5% had 6 (3/121), and 0.8% had 7 hemorrhagic episodes (1/121). With respect to all bleeding patients, the week in which bleeding occurred was 31.4 ± 3.3, with the highest incidence of bleeding occurring at 32 weeks of gestation at a rate of 14.6% (Fig. 1 ). No bleeding occurred after the 38th gestational week, as most placenta previa patients underwent elective CD at 36–37 weeks. If there was a history of bleeding, CD was performed before 37 weeks. The difference between bleeding in the second trimester (21.9%, 51/233) and bleeding in the third trimester (78.1%, 182/233) was statistically significant (χ 2 = 73.625, P = 0.000). Although we did not observe any statistical differences in the demographic characteristics between patients with or without APH (Table 1 ) (P > 0.05), there was a significant difference in placental classification (P < 0.05), particularly with respect to the complete-placenta category, where the bleeding group exhibited a higher prevalence than the non-bleeding group (72.9% vs 47.4%). Having complete-placental coverage was thus an independent risk factor for APH in placenta previa patients (OR, 4.17; 95% CI, 1.805–9.634). Table 1 Demographic and obstetric characteristics of the study Without APH With APH (n = 126) (n = 121) P value Age (years), mean ± SD 34.7 ± 4.6 34.9 ± 4.2 0.893 Gravidity, median (range) 2 (2–4) 3 (2–4) 0.172 Parity, median (range) 1 (0–2) 1 (1–2) 0.116 BMI (kg/m 2 ), mean ± SD 29.7 ± 5.2 29.1 ± 5.7 0.182 Smoking, n (%) 24 (19.0) 19 (15.7) 0.488 IVF, n (%) 31 (24.8) 33 (27.3) 0.659 Prior CD number, median (range) 0 (0–1) 0 (0–0) 0.217 CD history, n (%) 34 (27.0) 25 (20.7) 0.244 CD interval (year), median (range) 2.7 ± 4.3 2.9 ± 3.9 0.239 Fetal presentation, n (%) 0.590 vertex 110 (87.3) 100 (82.6) breech 9 (7.1) 12 (9.9) transverse 7 (5.6) 9 (7.4) GBS infection, n (%) 99 (88.4) 102 (87.9) 0.914 APH, antepartum hemorrhage. BMI, body mass index. IVF, in vitro fertilization. CD, cesarean delivery. GBS, group B streptococcus. The gestational week in which delivery occurred for patients without APH was much later than for patients with hemorrhage (37.1 ± 1.6 vs 35.6 ± 1.9, p = 0.000). Figure 2 depicts a Kaplan-Meier curve of the proportion of placenta previa patients with or without APH who remained undelivered at each gestational week, showing that 89.1% delivered beyond 34 weeks of gestation and that 53% delivered beyond 37 weeks of gestation. In addition to gestational week, we observed significant differences between the 2 groups with regard to maternal outcomes including length of hospital stay, first trimester and pre-operative levels of HGB and HCT, emergent CD, blood transfusion rate, total blood product, general anesthesia (GA), and American Society of Anesthesiologists (ASA) physical status classification (P < 0.05). There were no differences in placenta accreta (11.1% vs 13.2%, p = 0.611) or other parameters, including anesthesia time, procedural duration, total fluid infusion, EBL, PPH, hysterectomy, or intensive care unit (ICU) admission (P > 0.05) (Table 2 ). Table 2 Placental characteristics and maternal outcomes of cesarean delivery among parturients with placenta previa Without APH With APH (n = 126) (n = 121) P value ASA status, n (%) 0.049 1 13 (10.3) 6 (5.0) 2 95 (75.4) 85 (70.2) 3–4 18 (14.3) 30 (24.8) Placental location, n (%) 1.000 Anterior 31 (26.7) 30 (25.9) Posterior 66 (56.9) 67 (57.8) Lateral 5 (4.3) 5 (4.3) Anterior + posterior 14 (12.1) 14 (12.1) Placental classification, n (%) 0.000 Complete 55 (47.4) 86 (72.9) Incomplete 37 (31.9) 23 (19.0) Low lying 24 (20.7) 9 (7.6) Placenta accreta, n (%) 14 (11.1) 16 (13.2) 0.611 Emergent CD, n (%) 15 (11.9) 66 (54.5) 0.000 Duration of procedure (min), mean ± SD 63.6 ± 48.0 66.8 ± 45.9 0.801 Anesthetic type, n (%) 0.024 General anesthesia (GA) 1 (0.8) 9 (7.4) Neuraxial anesthesia (NA) 121 (96.0) 108 (89.3) NA converted to GA 4 (3.2) 4 (3.3) Anesthesia time (min), mean ± SD 123.8 ± 78.1 136.9 ± 116.0 0.114 EBL (ml), median (range) 800 (775–1000) 900 (800–1215) 0.109 PRBC product (ml), mean ± SD 1112.7 ± 812.4 863.0 ± 898.7 0.269 All blood products (ml), mean ± SD 238.3 ± 1046.4 297.5 ± 1170.4 0.045 Blood transfusion, n (%) 12 (9.5) 23 (19.0) 0.033 Total fluid infusion (ml), median (range) 1600 (1000–2000) 1500 (1100–2225) 0.395 HGB (g/dl), mean ± SD First trimester 12.4 ± 1.1 12.0 ± 1.2 0.022 Pre-operation 11.8 ± 1.3 11.2 ± 1.3 0.000 Post-operation 9.9 ± 2.5 9.5 ± 1.4 0.207 HCT (%), mean ± SD First trimester 36.8 ± 3.0 35.6 ± 3.6 0.012 Pre-operation 35.0 ± 3.1 33.3 ± 3.8 0.001 Post-operation 28.9 ± 3.7 28.4 ± 4.2 0.245 PPH, n (%) 46 (36.5) 56 (46.3) 0.119 Hysterectomy, n (%) 9 (7.1) 8 (6.6) 0.869 ICU admission, n (%) 3 (2.4) 1 (0.8) 0.643 Inpatient days (day), mean ± SD 4.6 ± 3.7 7.2 ± 7.2 0.000 APH, antepartum hemorrhage. ASA, the American Sociological Association. CD, cesarean delivery. EBL, estimated blood loss. PRBC, packed red blood cells. HGB, hemoglobin. HCT, hematocrit. PPH, postpartum hemorrhage. ICU, intensive care unit. Neonatal outcomes were also significantly different between the 2 groups. The APH group manifested a higher rate of preterm delivery and a lower birth weight (P < 0.001) relative to the non-bleeding group. Infants with an Apgar score of less than 7 at 1 minute had a higher prevalence of APH compared to those without APH (P = 0.003), but there was no difference in infants with an Apgar score of less than 7 at 5 minutes (P = 0.09). The number of newborns admitted to the neonatal intensive care unit (NICU) was also statistically different between the 2 groups, while the women with APH exhibited a higher admission rate than those without APH (P = 0.002) (Table 3 ). Table 3 Neonatal outcomes in parturients with placenta previa Without APH With APH (n = 126) (n = 121) P value Gestational age (weeks), mean ± SD 37.1 ± 1.6 35.6 ± 1.9 0.000 Newborn birth weight (grams), mean ± SD 2920 ± 524 2686 ± 544 0.000 Apgar score at 1 min, n (%) 0.003 ≤ 7 23 (18.3) 42 (34.7) > 7 103 (81.7) 79 (65.3) Apgar Score at 5 min, n (%) 0.090 ≤ 7 7 (5.6) 14 (11.6) > 7 119 (94.4) 107 (88.4) Preterm delivery, n (%) 41 (32.5) 90 (74.4) 0.000 Endotracheal intubation of newborns , n (%) 40 (31.7) 52 (43.3) 0.060 NICU admission, n (%) 47(37.3) 68 (56.7) 0.002 APH, antepartum hemorrhage. NICU, neonatal intensive care unit. Discussion: In our investigation, we observed that the prevalence of APH in patients with placenta previa was 49%, which is consistent with reports of 32.0–77.1% in other countries 2 , 3 , 9 – 12 , and similar to the 51.9% reported in a systematic review of studies worldwide. 13 We found that the number of APH events varied between 1 and 7 episodes, with nearly half of the patients experiencing 2–3 incidents throughout their pregnancies. The incidence of APH was distinct for each gestational week, with the 32nd gestational week appearing to be the most precarious and possessing the highest incidence of APH. We evaluated the incidence of APH in placenta previa patients as it was first described and during the gestational week in which it occurred, and to the best of our knowledge, there are no other extant reports on this specific topic. In general, the 32nd week marked a turning point in that prior to 32 weeks, bleeding gradually increased commensurate with increasing gestational week. However, after 32 weeks, the bleeding began to diminish. This pattern appears to be consistent with data demonstrating that as the numbers of CDs gradually increase commensurately with the increase in gestational weeks, the resulting incidence of vaginal bleeding is markedly reduced. 14 It is possible that augmented uterine contractions (particularly after 32 weeks) may lead to a shortened cervical length and further separation of the placenta from the uterine wall, thus allowing hemorrhaging to occur more readily. Previous investigators have postulated that the etiology of APH in placenta previa is a poor blood supply that induces atrophy of thin portions of the placenta implanted over the cervix; this subsequently leads to placental migration as gestation continues, ensuring an improved blood supply from a more richly vascularized area (a process known as trophotropism). 15 Oppenheimer et al. 16 reported that the placenta did not overlap the internal os consistently; rather, placental migration occurred at an average rate of + 5.4 mm/week, while the rate was only + 0.3 mm/week in placenta previa. 16 Uterine contractions, cervical effacement, and dilatation during the third trimester can also cause separation of the placenta, which leads to small amounts of bleeding; this bleeding may subsequently stimulate further placental separation and unavoidable hemorrhage. 17 Our finding of complete placenta previa as a risk factor for APH is consistent with prior studies. Bahar et al., for example, reported that women with major (complete or partial) placenta previa manifested a significantly higher incidence of APH (OR, 3.18; 95% CI, 1.58–6.4; P = 0.001). 3 Similarly, Atsuko et al. reported that APH was more prevalent in women with complete placenta previa compared to those with incomplete previa (59.1% vs. 17.6%: OR, 6.79; 95% CI, 3.31–13.92). 18 Yang et al. also reported a higher frequency of APH in complete previa compared to marginal previa. 19 From these studies, it appears that complete previa is likely to be an independent risk factor in predicting APH in these patients. Some authors have also used ultrasonography to identify short uterine cervical length (observed in the third trimester) and the sinus venosus at the margin of the placenta as risk factors for APH in placenta previa. 20 Stafford et al. demonstrated that in the third trimester, a cervical length of 30 mm or less was associated with an increased risk for hemorrhage (79% vs 28%) in placenta previa patients, 21 whereas Saitoh et al. reported that the risk of massive antenatal hemorrhage was higher (83.3%) in placenta previa patients with an echo-free space in the placental edge overlying the internal os compared to other locations (7.7–10%). 22 We must, however, admit that the evidence remains controversial, with other investigators showing contrasting results. Hasegawa et al. maintained that the use of ultrasonography could not predict bleeding episodes, 10 and according to the 2011 RCOG guidelines, APH possesses a heterogeneous pathophysiology and thereby cannot be predicted reliably. 7 Intriguingly, the location of the placenta was not reported to influence APH, 18 and the anterior placenta may only increase hemorrhage during and after CD. 23 Contradicting our original hypothesis, placenta accreta did not serve as a protective factor in ameliorating APH. With regard to maternal outcomes, we also demonstrated that recurrent or major APH enhanced hospitalizations, led to maternal anemia, and increased emergent CDs, blood transfusion rate, and total blood-product infusion; these findings were also confirmed by Takayama 24 and Crane et al. 25 Although these authors also reported that APH elevated rates of hysterectomy 24 and PPH, 25 , 26 we did not find an increase in bleeding with hysterectomy or PPH in our study. We additionally treated our hysterectomy or PPH patients with various hemostatic methods including uterine balloons, B-Lynch sutures, arterial ligation, or bilateral uterine artery embolization. We also found that patients with APH were more likely to have undergone general anesthesia, which was probably due to their greater chance of requiring emergent delivery. Since general anesthesia (GA) is associated with a higher risk for PPH in CD 27 – 29 , routine CDs are commonly performed using neuraxial anesthesia following guidelines that also recommend using neuraxial anesthesia in placenta previa. 1 In the present study, 4.0% of all patients underwent GA (consistent with a previous report by Markley et al. [5%]), 30 and of the patients who underwent GA, 70% underwent emergent CS for APH. It is possible that the massive bleeding associated with APH led to unstable maternal hemodynamics or intrauterine fetal hypoxia, which would not have allowed enough time to prepare for the use of neuraxial techniques. At our institution, electively scheduled CDs for placenta previa are performed at 36–37 weeks of gestation, and preterm CD is performed only when massive, uncontrollable hemorrhage or fetal distress occurs. The American Society for Maternal-Fetal Medicine (SMFM) and the RCOG guidelines both recommend delivery dates for placenta previa to be between 36 + 0 and 37 + 0 weeks of gestation for women who are stable and show no bleeding. 1 , 31 In placenta previa patients with a history of vaginal bleeding or other associated risk factors, delivery should be considered between 34 + 0 and 36 + 6 weeks of gestation. 1 SMFM also recommends that for women with active hemorrhaging in the late preterm period, delivery should not be delayed for the purpose of administering antenatal corticosteroids. 31 Many studies have shown that recurrent APH causes higher rates of NICU admission, preterm delivery, 32 stillbirth, death, 33 and other adverse neonatal outcomes 34 ,which is consistent with our current results. These adverse outcomes may be due to recurrent antenatal vaginal bleeding that affects the placental blood supply, which subsequently leads to insufficient fetal blood supply. 5 In contrast, however, some investigators have not found that severe bleeding leads to increased adverse maternal or neonatal outcomes. 35 The discrepancies among these aforementioned studies may reflect differences in maternal background and patient management, and suggest that additional large, multicenter studies are needed to confirm the effects of APH on both maternal and neonatal outcomes. To our knowledge, this is the first study to identify an association between APH in placenta previa patients and gestational week. Our work adds to the important literature regarding risk factors for APH and its significant implications for maternal and neonatal outcomes. Although it is difficult to reliably predict APH among women, we identified the third trimester—especially around 32 weeks—as a potential turning point with respect to bleeding risk. We also found complete placenta previa to be an independent risk factor for APH in this specific patient population. Several limitations to this study should be noted. First, this was a relatively small study limited to one healthcare system, which may result in informational and regional biases that require increased case numbers and an expanded research area. Second, because of the retrospective nature of the study design, we were unable to collect and report on data regarding other important information, including the amount of APH, cervical length, umbilical arterial blood gas values, and long-term neonatal complications. In the future, large prospective studies are needed to assist clinicians and researchers in better understanding the risks and implications of APH in placenta previa patients. Conclusions: The gestational week and frequency of APH varied by patient with placenta previa and might have resulted in an increase in adverse maternal and neonatal outcomes. Clinicians should thus be cognizant of placenta previa as increasing the risk for prenatal bleeding, especially in the third trimester at approximately the 32nd gestational week. It is also important for clinicians to recognize that women who do experience APH may be at higher risk for requiring blood transfusions and undergoing emergent CD, and their newborns are at an increased likelihood for manifesting lower birth weight, asphyxia, and additional NICU admissions. Pediatric involvement in the delivery of these patients may therefore be warranted. Thus, healthcare providers should consider transferring patients with complete placenta previa to a tertiary medical center to tailor their personal antenatal management, identify potential risks and outcomes, and provide advanced, multidisciplinary care to prevent adverse consequences. Abbreviations CD: Cesarean delivery; APH:Antepartum hemorrhage; PHS:Partners Healthcare System; EMR:Electronic medical records; BMI:Body mass index; IVF:In vitro fertilization; PRBC:Packed red blood cells; FFP:Fresh frozen plasma; PPH:Postpartum hemorrhage; EBL:Estimated blood loss; HGB:Hemoglobin; HCT:Hematocrit; SPSS:Statistical Package for the Social Sciences; SD:Standard deviation; OR:Odds ratio; CI:Confidence interval; GA:General anesthesia; SMFM:Society for Maternal-Fetal Medicine Declarations Acknowledgments We wish to thank Drs. Fan Li and Yan Gao of the Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School. Funding There were no funding sources for this study. Availability of data and materials The datasets analyzed during the current study are available from the corresponding author upon reasonable request. Authors’ contributions Wenjie Qing drafted the manuscript and participated in data collection and analysis; Linda Li analyzed data and prepared the manuscript; Alyssia Venna performed the statistical analysis and reviewed the manuscript; and Jie Zhou contributed to the development of the study, the study design, and manuscript preparation for publication. All authors read and approved the final manuscript. Ethics approval and consent to participate The authors confirm that they obtained approval by the Ethics Committee of Brigham and Women’s Hospital, Harvard Medical School; and that written consent for use of the data in scientific research was also acquired from patients before operation. Consent for publication Not applicable. 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Ultrasonographic cervical length and risk of hemorrhage in pregnancies with placenta previa. Obstet Gynecol. 2010;116:595–600. Saitoh M, Ishihara K, Sekiya T, Araki T. Anticipation of uterine bleeding in placenta previa based on vaginal sonographic evaluation. Gynecol Obstet Invest. 2002;54:37–42. Baba Y, Matsubara S, Ohkuchi A, Usui R, Kuwata T, Suzuki H, et al. Anterior placentation as a risk factor for massive hemorrhage cesarean section in patients with placenta previa. J Obstet Gynaecol Res. 2014;40:1243–8. Takayama T, Minakami H, Koike T, Watanabe T, Sato I. Risks associated with cesarean sections in women with placenta previa. J Obstet Gynaecol Res. 1997;23:375–9. Crane JM, Van den Hof MC, Dodds L, Armson BA, Liston R. Maternal complications with placenta previa. Am J Perinatol. 2000;17:101–5. Stones RW, Paterson CM, StG Saunders NJ. Risk factors for major obstetric haemorrhage. European Journal of Obstetrics Gynecology Reproductive Biology. 1993;48:15–8. Snegovskikh D, Clebone A, Norwitz E. Anesthetic management of patients with placenta accreta and resuscitation strategies for associated massive hemorrhage. Curr Opin Anaesthesiol. 2011;24:274–81. Weiniger CF, Einav S, Deutsch L, Ginosar Y, Ezra Y, Eid L. Outcomes of prospectively-collected consecutive cases of antenatal-suspected placenta accreta. Int J Obstet Anesth. 2013;22:273–9. Wise A, Clark V. Strategies to manage major obstetric haemorrhage. Curr Opin Anaesthesiol. 2008;21:281–7. Markley JC, Farber MK, Perlman NC, Carusi DA. Neuraxial Anesthesia During Cesarean Delivery for Placenta Previa With Suspected Morbidly Adherent Placenta: A Retrospective Analysis. Anesth Analg. 2018;127:930–38. Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of bleeding in the late preterm period. Am J Obstet Gynecol. 2018;218:B2-b8. Bhandari S, Raja EA, Shetty A, Bhattacharya S. Maternal and perinatal consequences of antepartum haemorrhage of unknown origin. BJOG. 2014;121:44–50. discussion 50 – 2. Schneiderman M, Balayla J. A comparative study of neonatal outcomes in placenta previa versus cesarean for other indication at term. J Matern Fetal Neonatal Med. 2013;26:1121–7. Rosenberg T, Pariente G, Sergienko R, Wiznitzer A, Sheiner E. Critical analysis of risk factors and outcome of placenta previa. Arch Gynecol Obstet. 2011;284:47–51. Mastrolia SA, Baumfeld Y, Loverro G, Yohai D, Hershkovitz R, Weintraub AY. Placenta previa associated with severe bleeding leading to hospitalization and delivery: a retrospective population-based cohort study. J Matern Fetal Neonatal Med. 2016;29:3467–71. Cite Share Download PDF Status: Published Journal Publication published 01 Jan, 2021 Read the published version in Clinical and Experimental Obstetrics & Gynecology → 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-61700","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research article","associatedPublications":[],"authors":[{"id":1599229,"identity":"08a1d2b8-3674-406d-9a87-afd389c4b8cd","order_by":0,"name":"Wenjie Qing","email":"","orcid":"","institution":"Chengdu women's and children's central hospital, the affiliated hospital, school of medicine, university of electronic science and technology of china","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Wenjie","middleName":"","lastName":"Qing","suffix":""},{"id":1599230,"identity":"8693474d-c306-4ef4-a35e-a85f7fe32cb9","order_by":1,"name":"Linda Li","email":"","orcid":"","institution":"Brigham and women's hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Linda","middleName":"","lastName":"Li","suffix":""},{"id":1599231,"identity":"76e647a3-b22e-4b7d-8425-f1261071b04a","order_by":2,"name":"Alyssia Venna","email":"","orcid":"","institution":"Brigham and women's hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Alyssia","middleName":"","lastName":"Venna","suffix":""},{"id":1599232,"identity":"a4a4b5d3-02a9-49d8-a36f-6fc47ac25631","order_by":3,"name":"Jie Zhou","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYBACxgYeIPHHJoFBgoENKpbAwMBDUEtDGglawLKMDYdJ0MLcf/bgY94d5/MMbjewPfi557C8eXsC44O3bfgcdi7ZmPfM7WKDOwfYDXueHTacc+YBs+FcfFoae8ykedhuJ267kcAmwXMgjXGGRAKbNC8+Lc08IC3nwFok/xxIswdqYf+NV0sbUAtv2wGwFmmeAzaJIFuY8Wrp4TEGOj+52P5GYpu0zAGb5Bk8D5sl55zDrcWw/4zhgzcVdnmSM5KPSb45IGE7gz354Ic3ZXi0NCAsbEBnYAfyeGVHwSgYBaNgFIAAAGEWUmCq6VSEAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0003-3031-3895","institution":"Brigham and women's hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Zhou","suffix":""}],"badges":[],"createdAt":"2020-08-18 11:30:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-61700/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-61700/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.31083/j.ceog4806226","type":"published","date":"2021-01-01T08:34:26+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":2027492,"identity":"83b4fa39-afaa-4a00-a310-154b380cb9fe","added_by":"auto","created_at":"2020-08-21 16:19:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":15895,"visible":true,"origin":"","legend":"Figure 1","description":"","filename":"Onlinefloatimage1.Png","url":"https://assets-eu.researchsquare.com/files/rs-61700/v1/Onlinefloatimage1.Png"},{"id":2027493,"identity":"8feb697b-76a3-427a-a007-f3e1ae342d37","added_by":"auto","created_at":"2020-08-21 16:19:25","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":9469,"visible":true,"origin":"","legend":"Figure 2","description":"","filename":"Onlinefloatimage2.Png","url":"https://assets-eu.researchsquare.com/files/rs-61700/v1/Onlinefloatimage2.Png"},{"id":16468385,"identity":"6d8b8721-2f31-4cb0-b0dc-c429b99f0501","added_by":"auto","created_at":"2021-12-15 08:34:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":514313,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-61700/v1/8c5481f6-b90d-4a3b-acbc-d5f6680fb5c8.pdf"}],"financialInterests":"","formattedTitle":"Influence of antepartum hemorrhage on placenta previa: A multi-center, retrospective cohort study","fulltext":[{"header":"Background:","content":" \u003cp\u003ePlacenta previa\u0026mdash;a condition where the placenta lies directly over the internal os\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e\u0026mdash;is a serious obstetric complication that leads to increased maternal and neonatal mortality and morbidity; its incidence is reported to vary between 0.15% and 0.91%. \u003csup\u003e\u003cspan additionalcitationids=\"CR3 CR4 CR5\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Clinically, placenta previa presents as recurrent painless vaginal bleeding in the antenatal period and massive hemorrhage during cesarean delivery (CD) and postoperatively. Antepartum hemorrhage (APH) is defined as bleeding from or into the genital tract that occurs from 24\u003csup\u003e+\u0026thinsp;0\u003c/sup\u003e weeks of pregnancy and prior to the birth of the baby.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e However, not all patients with placenta previa encounter APH, and some may not experience any bleeding during the entire prenatal period. It is thus currently unclear as to which risk factors contribute to APH or at which gestational week bleeding occurs. To our knowledge, there are no extant studies in the literature that describe the relationship between APH and gestational week.\u003c/p\u003e \u003cp\u003eGiven the importance yet paucity of the existing literature on this topic, the aims of the current study were to identify the following in placenta previa patients: 1) the relationship between APH and gestational week, 2) risk factors for APH, and 3) whether patients with APH developed more severe adverse perinatal outcomes. This knowledge will help to improve the antenatal management of placenta previa and optimize prophylactic measures to ameliorate outcomes.\u003c/p\u003e "},{"header":"Methods:","content":" \u003cp\u003eThe present investigation was a multi-center, retrospective study approved by the Institutional Review Board at Partners Healthcare System (PHS) (Protocol#2019P000028). We collected all patient delivery data between October of 2015 and September of 2018 within PHS; this includes 7 different hospitals, 2 of which are large, tertiary, academic medical centers. The total number of deliveries during this period was 39,945, including 12,884 cesarean deliveries (32.3%) and 27,061 vaginal deliveries (67.7%). We sought patients in the PHS using the indication of placenta previa for \u0026ldquo;cesarean section\u0026rdquo; or \u0026ldquo;cesarean delivery\u0026rdquo;, and found 259 patients who met this criterion. At our institution, whenever placenta previa was identified by ultrasonography in the second trimester, a follow-up ultrasonographic examination was performed at 32\u0026ndash;34 weeks of gestation to evaluate the relationship between the placenta and the cervix. All included cases were consistent with the ultrasonographic image produced before CD.\u003c/p\u003e \u003cp\u003eTo avoid data bias in maternal and newborn outcomes, we excluded patients with multiple pregnancies (n\u0026thinsp;=\u0026thinsp;8), stillbirths (n\u0026thinsp;=\u0026thinsp;1), or delivery at less than 24 weeks of gestational age (n\u0026thinsp;=\u0026thinsp;3). A total of 247 patients were ultimately included in our study.\u003c/p\u003e \u003cp\u003eDemographic data were collected from electronic medical records (EMR) and included maternal age, gravidity, parity, body mass index (BMI), smoking history, in vitro fertilization (IVF) history, prior number of CDs, history of CDs, and duration of the CD interval. The interval duration depicted the interval between the most recent CD and the current delivery. Gestational week was either calculated using the date of the last menstrual period or estimated from the first-trimester ultrasonographic measurements. We obtained placental location and classification from the last ultrasonographic report prior to delivery, and this was validated during CD. The placenta was classified as either complete, incomplete (marginal or partial), or low lying. Placenta accreta was recorded from patient surgical records and confirmed by pathologic diagnosis. We also located maternal and neonatal outcomes in the surgical records as well as in anesthesia and neonatal records. The intraoperative variable of \u0026ldquo;total blood product\u0026rdquo; represented the sum total (units) of any blood product administered during the operative period, including packed red blood cells (PRBC), cell salvage, fresh frozen plasma (FFP), platelets, cryoprecipitate, and albumin. We defined postpartum hemorrhage (PPH) as an estimated blood loss (EBL) over 1000\u0026nbsp;ml. Hemoglobin (HGB) concentration and hematocrit (HCT) percentage during the first trimester, pre-operation, and postoperatively were procured from laboratory results found in the EMR.\u003c/p\u003e \u003cp\u003eAll vaginal bleeding was recorded in our data, including the number of bleeding episodes and specific gestational week when bleeding occurred. Persistent bleeding was recorded once at the beginning of bleeding; however, if the patient experienced an interval without bleeding for more than 1 week, then the next bleeding was considered a second bleeding incident. Repeated bleeding was recorded several times according to the number of bleeding episodes. All hemorrhages were recorded, including those that occurred during inpatient and outpatient visits; however, bleeding caused by labor was not included. We observed no bleeding caused by neoplasm, infection, trauma, or iatrogenesis in any of our cases. There was also no bleeding due to vasa previa or placental abruption. The amount of bleeding was not included in our data as the majority was not quantified. All included cases met the recommendations and guidelines for data collection and analysis for APH in placenta previa.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWe conducted our statistical analysis using the Statistical Package for Social Sciences (SPSS) software, version 23.0. Continuous variables are presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;1 standard deviation (SD) or medians with an inter-quartile range, and we made comparisons between placenta previa with or without APH using the independent-sample \u003cem\u003et\u003c/em\u003e test or non-parametric Mann-Whitney U test depending upon normality of the data distribution. Categorical variables are shown as counts and percentages, and the differences were assessed using Chi-squared analysis; Fisher\u0026rsquo;s exact-probability test was used when appropriate. A value of P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. We used logistic regression to study the independent risk factors for APH: the dependent variable was APH, and age, gravidity, parity, BMI, history of CD, number of prior CDs, duration of CD interval, placental location, and placental classification all served as covariates, with P\u0026thinsp;\u0026lt;\u0026thinsp;0.01 representing a significant difference. Results are reported using odds ratios (OR) and 95% confidence intervals (CI). We used a Kaplan-Meier survival curve to show placenta previa patients with or without APH who remained undelivered at each gestational week.\u003c/p\u003e "},{"header":"Results:","content":" \u003cp\u003eThe prevalence of placenta previa in our study was 0.65% (259/39945), and the mean number of gestational weeks at delivery was 36.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5. We identified 247 patients who underwent CD for placenta previa: 17 of these underwent a hysterectomy (6.9%, 17/247), 7 were treated with a uterine balloon (2.8%, 7/247), 3 underwent bilateral uterine artery embolization (1.2%, 3/247), and 7 patients received ureteral stents (2.8%, 7/247).\u003c/p\u003e \u003cp\u003eThe incidence of APH in placenta previa was 49.0% (121/247). The mean number of bleeding episodes was 2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3. While most experienced a one-time bleeding episode (36.4%, 44/121), 26.4% had 2 (32/121), 23.1% had 3 (28/121), 9.1% had 4 (11/121), 1.7% had 5 (2/121), 2.5% had 6 (3/121), and 0.8% had 7 hemorrhagic episodes (1/121). With respect to all bleeding patients, the week in which bleeding occurred was 31.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3, with the highest incidence of bleeding occurring at 32 weeks of gestation at a rate of 14.6% (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). No bleeding occurred after the 38th gestational week, as most placenta previa patients underwent elective CD at 36\u0026ndash;37 weeks. If there was a history of bleeding, CD was performed before 37 weeks. The difference between bleeding in the second trimester (21.9%, 51/233) and bleeding in the third trimester (78.1%, 182/233) was statistically significant (χ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;73.625, P\u0026thinsp;=\u0026thinsp;0.000).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAlthough we did not observe any statistical differences in the demographic characteristics between patients with or without APH (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05), there was a significant difference in placental classification (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), particularly with respect to the complete-placenta category, where the bleeding group exhibited a higher prevalence than the non-bleeding group (72.9% vs 47.4%). Having complete-placental coverage was thus an independent risk factor for APH in placenta previa patients (OR, 4.17; 95% CI, 1.805\u0026ndash;9.634).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic and obstetric characteristics of the study\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWithout APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWith APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;126)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;121)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge (years), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.893\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGravidity, median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (2\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (2\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.172\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eParity, median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (0\u0026ndash;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (1\u0026ndash;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.116\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI (kg/m\u003c/b\u003e\u003csup\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e29.7\u0026thinsp;\u0026plusmn;\u0026thinsp;5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.182\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSmoking, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24 (19.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (15.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.488\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIVF, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (24.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33 (27.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.659\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePrior CD number, median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0\u0026ndash;1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0\u0026ndash;0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.217\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCD history, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34 (27.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (20.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.244\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCD interval (year), median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.239\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFetal presentation, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.590\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003evertex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e110 (87.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100 (82.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebreech\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (7.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (9.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003etransverse\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGBS infection, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e99 (88.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102 (87.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.914\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eAPH, antepartum hemorrhage. BMI, body mass index. IVF, in vitro fertilization. CD, cesarean delivery. GBS, group B streptococcus.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe gestational week in which delivery occurred for patients without APH was much later than for patients with hemorrhage (37.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 vs 35.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9, p\u0026thinsp;=\u0026thinsp;0.000). Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e depicts a Kaplan-Meier curve of the proportion of placenta previa patients with or without APH who remained undelivered at each gestational week, showing that 89.1% delivered beyond 34 weeks of gestation and that 53% delivered beyond 37 weeks of gestation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition to gestational week, we observed significant differences between the 2 groups with regard to maternal outcomes including length of hospital stay, first trimester and pre-operative levels of HGB and HCT, emergent CD, blood transfusion rate, total blood product, general anesthesia (GA), and American Society of Anesthesiologists (ASA) physical status classification (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). There were no differences in placenta accreta (11.1% vs 13.2%, p\u0026thinsp;=\u0026thinsp;0.611) or other parameters, including anesthesia time, procedural duration, total fluid infusion, EBL, PPH, hysterectomy, or intensive care unit (ICU) admission (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePlacental characteristics and maternal outcomes of cesarean delivery among parturients with placenta previa\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWithout APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWith APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;126)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;121)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASA status, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.049\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (10.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e95 (75.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e85 (70.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u0026ndash;4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (24.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePlacental location, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (26.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (25.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e66 (56.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e67 (57.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (4.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (4.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior\u0026thinsp;+\u0026thinsp;posterior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (12.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (12.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePlacental classification, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComplete\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55 (47.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e86 (72.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIncomplete\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37 (31.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (19.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow lying\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24 (20.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (7.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePlacenta accreta, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (13.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.611\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEmergent CD, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (11.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66 (54.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDuration of procedure (min), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e63.6\u0026thinsp;\u0026plusmn;\u0026thinsp;48.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66.8\u0026thinsp;\u0026plusmn;\u0026thinsp;45.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.801\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAnesthetic type, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.024\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGeneral anesthesia (GA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (7.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeuraxial anesthesia (NA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e121 (96.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e108 (89.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNA converted to GA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAnesthesia time (min), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e123.8\u0026thinsp;\u0026plusmn;\u0026thinsp;78.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e136.9\u0026thinsp;\u0026plusmn;\u0026thinsp;116.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.114\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEBL (ml), median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e800 (775\u0026ndash;1000)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e900 (800\u0026ndash;1215)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.109\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePRBC product (ml), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1112.7\u0026thinsp;\u0026plusmn;\u0026thinsp;812.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e863.0\u0026thinsp;\u0026plusmn;\u0026thinsp;898.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.269\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAll blood products (ml), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e238.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1046.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e297.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1170.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.045\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBlood transfusion, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (9.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (19.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.033\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTotal fluid infusion (ml), median (range)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1600 (1000\u0026ndash;2000)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1500 (1100\u0026ndash;2225)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.395\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHGB (g/dl), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFirst trimester\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.022\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePost-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.207\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHCT (%), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFirst trimester\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.012\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePost-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.4\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.245\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePPH, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46 (36.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e56 (46.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.119\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHysterectomy, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (7.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (6.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.869\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eICU admission, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (2.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.643\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eInpatient days (day), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.2\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eAPH, antepartum hemorrhage. ASA, the American Sociological Association. CD, cesarean delivery. EBL, estimated blood loss. PRBC, packed red blood cells. HGB, hemoglobin. HCT, hematocrit. PPH, postpartum hemorrhage. ICU, intensive care unit.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNeonatal outcomes were also significantly different between the 2 groups. The APH group manifested a higher rate of preterm delivery and a lower birth weight (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) relative to the non-bleeding group. Infants with an Apgar score of less than 7\u0026nbsp;at 1 minute had a higher prevalence of APH compared to those without APH (P\u0026thinsp;=\u0026thinsp;0.003), but there was no difference in infants with an Apgar score of less than 7\u0026nbsp;at 5 minutes (P\u0026thinsp;=\u0026thinsp;0.09). The number of newborns admitted to the neonatal intensive care unit (NICU) was also statistically different between the 2 groups, while the women with APH exhibited a higher admission rate than those without APH (P\u0026thinsp;=\u0026thinsp;0.002) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNeonatal outcomes in parturients with placenta previa\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWithout APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWith APH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;126)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e(n\u0026thinsp;=\u0026thinsp;121)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003eP value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGestational age (weeks), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNewborn birth weight (grams), mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2920\u0026thinsp;\u0026plusmn;\u0026thinsp;524\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2686\u0026thinsp;\u0026plusmn;\u0026thinsp;544\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eApgar score at 1\u0026nbsp;min, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (18.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42 (34.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e103 (81.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e79 (65.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eApgar Score at 5\u0026nbsp;min, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.090\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (11.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e119 (94.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e107 (88.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePreterm delivery, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41 (32.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e90 (74.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEndotracheal intubation of newborns\u003c/b\u003e,\u003c/p\u003e \u003cp\u003e\u003cb\u003en (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40 (31.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52 (43.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNICU admission, n (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e47(37.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68 (56.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eAPH, antepartum hemorrhage. NICU, neonatal intensive care unit.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e "},{"header":"Discussion:","content":" \u003cp\u003eIn our investigation, we observed that the prevalence of APH in patients with placenta previa was 49%, which is consistent with reports of 32.0\u0026ndash;77.1% in other countries\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, and similar to the 51.9% reported in a systematic review of studies worldwide.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWe found that the number of APH events varied between 1 and 7 episodes, with nearly half of the patients experiencing 2\u0026ndash;3 incidents throughout their pregnancies. The incidence of APH was distinct for each gestational week, with the 32nd gestational week appearing to be the most precarious and possessing the highest incidence of APH. We evaluated the incidence of APH in placenta previa patients as it was first described and during the gestational week in which it occurred, and to the best of our knowledge, there are no other extant reports on this specific topic. In general, the 32nd week marked a turning point in that prior to 32 weeks, bleeding gradually increased commensurate with increasing gestational week. However, after 32 weeks, the bleeding began to diminish. This pattern appears to be consistent with data demonstrating that as the numbers of CDs gradually increase commensurately with the increase in gestational weeks, the resulting incidence of vaginal bleeding is markedly reduced.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e It is possible that augmented uterine contractions (particularly after 32 weeks) may lead to a shortened cervical length and further separation of the placenta from the uterine wall, thus allowing hemorrhaging to occur more readily. Previous investigators have postulated that the etiology of APH in placenta previa is a poor blood supply that induces atrophy of thin portions of the placenta implanted over the cervix; this subsequently leads to placental migration as gestation continues, ensuring an improved blood supply from a more richly vascularized area (a process known as trophotropism).\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e Oppenheimer et al. \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e reported that the placenta did not overlap the internal os consistently; rather, placental migration occurred at an average rate of +\u0026thinsp;5.4\u0026nbsp;mm/week, while the rate was only\u0026thinsp;+\u0026thinsp;0.3\u0026nbsp;mm/week in placenta previa.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Uterine contractions, cervical effacement, and dilatation during the third trimester can also cause separation of the placenta, which leads to small amounts of bleeding; this bleeding may subsequently stimulate further placental separation and unavoidable hemorrhage.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eOur finding of complete placenta previa as a risk factor for APH is consistent with prior studies. Bahar et al., for example, reported that women with major (complete or partial) placenta previa manifested a significantly higher incidence of APH (OR, 3.18; 95% CI, 1.58\u0026ndash;6.4; P\u0026thinsp;=\u0026thinsp;0.001).\u003csup\u003e3\u003c/sup\u003e Similarly, Atsuko et al. reported that APH was more prevalent in women with complete placenta previa compared to those with incomplete previa (59.1% vs. 17.6%: OR, 6.79; 95% CI, 3.31\u0026ndash;13.92).\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Yang et al. also reported a higher frequency of APH in complete previa compared to marginal previa.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e From these studies, it appears that complete previa is likely to be an independent risk factor in predicting APH in these patients. Some authors have also used ultrasonography to identify short uterine cervical length (observed in the third trimester) and the sinus venosus at the margin of the placenta as risk factors for APH in placenta previa.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e Stafford et al. demonstrated that in the third trimester, a cervical length of 30\u0026nbsp;mm or less was associated with an increased risk for hemorrhage (79% vs 28%) in placenta previa patients,\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e whereas Saitoh et al. reported that the risk of massive antenatal hemorrhage was higher (83.3%) in placenta previa patients with an echo-free space in the placental edge overlying the internal os compared to other locations (7.7\u0026ndash;10%).\u003csup\u003e22\u003c/sup\u003e We must, however, admit that the evidence remains controversial, with other investigators showing contrasting results. Hasegawa et al. maintained that the use of ultrasonography could not predict bleeding episodes,\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e and according to the 2011 RCOG guidelines, APH possesses a heterogeneous pathophysiology and thereby cannot be predicted reliably.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Intriguingly, the location of the placenta was not reported to influence APH,\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e and the anterior placenta may only increase hemorrhage during and after CD.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e Contradicting our original hypothesis, placenta accreta did not serve as a protective factor in ameliorating APH.\u003c/p\u003e \u003cp\u003eWith regard to maternal outcomes, we also demonstrated that recurrent or major APH enhanced hospitalizations, led to maternal anemia, and increased emergent CDs, blood transfusion rate, and total blood-product infusion; these findings were also confirmed by Takayama\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e and Crane et al.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e Although these authors also reported that APH elevated rates of hysterectomy\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e and PPH,\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e we did not find an increase in bleeding with hysterectomy or PPH in our study. We additionally treated our hysterectomy or PPH patients with various hemostatic methods including uterine balloons, B-Lynch sutures, arterial ligation, or bilateral uterine artery embolization. We also found that patients with APH were more likely to have undergone general anesthesia, which was probably due to their greater chance of requiring emergent delivery. Since general anesthesia (GA) is associated with a higher risk for PPH in CD\u003csup\u003e\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e, routine CDs are commonly performed using neuraxial anesthesia following guidelines that also recommend using neuraxial anesthesia in placenta previa.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e In the present study, 4.0% of all patients underwent GA (consistent with a previous report by Markley et al. [5%]),\u003csup\u003e30\u003c/sup\u003e and of the patients who underwent GA, 70% underwent emergent CS for APH. It is possible that the massive bleeding associated with APH led to unstable maternal hemodynamics or intrauterine fetal hypoxia, which would not have allowed enough time to prepare for the use of neuraxial techniques. At our institution, electively scheduled CDs for placenta previa are performed at 36\u0026ndash;37 weeks of gestation, and preterm CD is performed only when massive, uncontrollable hemorrhage or fetal distress occurs. The American Society for Maternal-Fetal Medicine (SMFM) and the RCOG guidelines both recommend delivery dates for placenta previa to be between 36\u003csup\u003e+\u0026thinsp;0\u003c/sup\u003e and 37\u003csup\u003e+\u0026thinsp;0\u003c/sup\u003e weeks of gestation for women who are stable and show no bleeding.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e In placenta previa patients with a history of vaginal bleeding or other associated risk factors, delivery should be considered between 34\u003csup\u003e+\u0026thinsp;0\u003c/sup\u003e and 36\u003csup\u003e+\u0026thinsp;6\u003c/sup\u003e weeks of gestation.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e SMFM also recommends that for women with active hemorrhaging in the late preterm period, delivery should not be delayed for the purpose of administering antenatal corticosteroids. \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eMany studies have shown that recurrent APH causes higher rates of NICU admission, preterm delivery,\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e stillbirth, death,\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e and other adverse neonatal outcomes\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e,which is consistent with our current results. These adverse outcomes may be due to recurrent antenatal vaginal bleeding that affects the placental blood supply, which subsequently leads to insufficient fetal blood supply.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e In contrast, however, some investigators have not found that severe bleeding leads to increased adverse maternal or neonatal outcomes.\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e The discrepancies among these aforementioned studies may reflect differences in maternal background and patient management, and suggest that additional large, multicenter studies are needed to confirm the effects of APH on both maternal and neonatal outcomes.\u003c/p\u003e \u003cp\u003eTo our knowledge, this is the first study to identify an association between APH in placenta previa patients and gestational week. Our work adds to the important literature regarding risk factors for APH and its significant implications for maternal and neonatal outcomes. Although it is difficult to reliably predict APH among women, we identified the third trimester\u0026mdash;especially around 32 weeks\u0026mdash;as a potential turning point with respect to bleeding risk. We also found complete placenta previa to be an independent risk factor for APH in this specific patient population.\u003c/p\u003e \u003cp\u003eSeveral limitations to this study should be noted. First, this was a relatively small study limited to one healthcare system, which may result in informational and regional biases that require increased case numbers and an expanded research area. Second, because of the retrospective nature of the study design, we were unable to collect and report on data regarding other important information, including the amount of APH, cervical length, umbilical arterial blood gas values, and long-term neonatal complications. In the future, large prospective studies are needed to assist clinicians and researchers in better understanding the risks and implications of APH in placenta previa patients.\u003c/p\u003e "},{"header":"Conclusions:","content":" \u003cp\u003eThe gestational week and frequency of APH varied by patient with placenta previa and might have resulted in an increase in adverse maternal and neonatal outcomes. Clinicians should thus be cognizant of placenta previa as increasing the risk for prenatal bleeding, especially in the third trimester at approximately the 32nd gestational week. It is also important for clinicians to recognize that women who do experience APH may be at higher risk for requiring blood transfusions and undergoing emergent CD, and their newborns are at an increased likelihood for manifesting lower birth weight, asphyxia, and additional NICU admissions. Pediatric involvement in the delivery of these patients may therefore be warranted. Thus, healthcare providers should consider transferring patients with complete placenta previa to a tertiary medical center to tailor their personal antenatal management, identify potential risks and outcomes, and provide advanced, multidisciplinary care to prevent adverse consequences.\u003c/p\u003e "},{"header":"Abbreviations","content":" \u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCD: Cesarean delivery; APH:Antepartum hemorrhage; PHS:Partners Healthcare System; EMR:Electronic medical records; BMI:Body mass index; IVF:In vitro fertilization; PRBC:Packed red blood cells; FFP:Fresh frozen plasma; PPH:Postpartum hemorrhage; EBL:Estimated blood loss; HGB:Hemoglobin; HCT:Hematocrit; SPSS:Statistical Package for the Social Sciences; SD:Standard deviation; OR:Odds ratio; CI:Confidence interval; GA:General anesthesia; SMFM:Society for Maternal-Fetal Medicine\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe wish to thank Drs. Fan Li and Yan Gao of the Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women\u0026rsquo;s Hospital, Harvard Medical School.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere were no funding sources for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWenjie Qing drafted the manuscript and participated in data collection and analysis; Linda Li analyzed data and prepared the manuscript; Alyssia Venna performed the statistical analysis and reviewed the manuscript; and Jie Zhou contributed to the development of the study, the study design, and manuscript preparation for publication.\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors confirm that they obtained approval by the Ethics Committee of Brigham and Women\u0026rsquo;s Hospital, Harvard Medical School; and that written consent for use of the data in scientific research was also acquired from patients before operation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll the authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e \u003cspan\u003eJauniaux E, Alfirevic Z, Behide AG, Belfort MA, Burton GJ, Collins SL, et al, Royal College of Obstetricians and Gynaecologists. Placenta praevia and placenta accreta: diagnosis and management. Green-top Guideline No. 27a. \u003cem\u003eBrit J Obtet Gyaecol\u003c/em\u003e 2019;126:e1-e48.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eKollmann M, Gaulhofer J, Lang U, Klaritsch P. Placenta praevia: incidence, risk factors and outcome. \u003cem\u003eJ Matern Fetal Neonatal Med\u003c/em\u003e 2016, 29:1395\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBahar A, Abusham A, Eskandar M, Sobande A, Alsunaidi M. Risk factors and pregnancy outcome in different types of placenta previa. Journal of obstetrics gynaecology Canada: JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC. 2009;31:126\u0026ndash;31.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eCresswell JA, Ronsmans C, Calvert C, Filippi V. Prevalence of placenta praevia by world region: a systematic review and meta-analysis. Tropical medicine \u0026amp; international health: TM \u0026amp; IH 2013;18:712 \u0026ndash; 24.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eJing L, Wei G, Mengfan S, Yanyan H. Effect of site of placentation on pregnancy outcomes in patients with placenta previa. PloS one. 2018;13:e0200252.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eRaisanen S, Kancherla V, Kramer MR, Gissler M, Heinonen S. Placenta previa and the risk of delivering a small-for-gestational-age newborn. Obstet Gynecol. 2014;124:285\u0026ndash;91.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eGynaecologists RCoO. Antepartum Haemorrhage. Green-top Guideline No63 2011;London.2\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003ePrabhu M, Eckert LO, Belfort M, Babarinsa I, Ananth CV, Sliver RM, et al. Antenatal bleeding: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data. Vaccine. 2017;35:6529\u0026ndash;37.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBhide A, Prefumo F, Moore J, Hollis B, Thilaganathan B. Placental edge to internal os distance in the late third trimester and mode of delivery in placenta praevia. Bjog. 2003;110:860\u0026ndash;4.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eHasegawa J, Higashi M, Takahashi S, Mimura T, Nakamura M, Matsuoka R, et al. Can ultrasonography of the placenta previa predict antenatal bleeding? Journal of clinical ultrasound: JCU. 2011;39:458\u0026ndash;62.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eWortman AC, Twickler DM, McIntire DD, Dashe JS. Bleeding complications in pregnancies with low-lying placenta. J Matern Fetal Neonatal Med. 2016;29:1367\u0026ndash;71.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eGiambattista E, Ossola MW, Duiella SF, Crovetto F, Acaia B, Somigliana E, et al. Predicting factors for emergency peripartum hysterectomy in women with placenta previa. Arch Gynecol Obstet. 2012;285:901\u0026ndash;6.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eFan D, Wu S, Liu L, Xia Q, Wang W, Guo XL, et al. Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis. Sci Rep. 2017;7:40320.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eRac MW, Wells CE, Twickler DM, Moschos E, McIntire DD, Dashe JS. Placenta accreta and vaginal bleeding according to gestational age at delivery. Obstet Gynecol. 2015;125:808\u0026ndash;13.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eHasegawa J. Sonoembryological evaluations of the development of placenta previa and velamentous cord insertion. J Obstet Gynaecol Res. 2015;41:1\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eOppenheimer L, Holmes P, Simpson N, Dabrowski A. Diagnosis of low-lying placenta: can migration in the third trimester predict outcome? Ultrasound in obstetrics \u0026amp; gynecology: the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 2001;18:100-2.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eOyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol. 2006;107:927\u0026ndash;41.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSekiguchi A, Nakai A, Kawabata I, Hayashi M, Takeshita T. Type and Location of Placenta Previa Affect Preterm Delivery Risk Related to Antepartum Hemorrhage. Int J Med Sci. 2013;10:1683\u0026ndash;88.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eYang XL, Zhou YF, Huang Y, Zhang R, Yang HX. [Analysis of obstetric outcomes for different types of placenta previa]. Zhonghua yi xue za zhi. 2013;93:849\u0026ndash;51.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eHasegawa J, Nakamura M, Hamada S, Matsuoka R, Ichizuka K, Sekizawa A, et al. Prediction of hemorrhage in placenta previa. Taiwanese journal of obstetrics \u0026amp; gynecology 2012;51:3\u0026ndash;6.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eStafford IA, Dashe JS, Shivvers SA, Alexander JM, McIntire DD, Leveno KJ. Ultrasonographic cervical length and risk of hemorrhage in pregnancies with placenta previa. Obstet Gynecol. 2010;116:595\u0026ndash;600.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSaitoh M, Ishihara K, Sekiya T, Araki T. Anticipation of uterine bleeding in placenta previa based on vaginal sonographic evaluation. Gynecol Obstet Invest. 2002;54:37\u0026ndash;42.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBaba Y, Matsubara S, Ohkuchi A, Usui R, Kuwata T, Suzuki H, et al. Anterior placentation as a risk factor for massive hemorrhage cesarean section in patients with placenta previa. J Obstet Gynaecol Res. 2014;40:1243\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eTakayama T, Minakami H, Koike T, Watanabe T, Sato I. Risks associated with cesarean sections in women with placenta previa. J Obstet Gynaecol Res. 1997;23:375\u0026ndash;9.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eCrane JM, Van den Hof MC, Dodds L, Armson BA, Liston R. Maternal complications with placenta previa. Am J Perinatol. 2000;17:101\u0026ndash;5.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eStones RW, Paterson CM, StG Saunders NJ. Risk factors for major obstetric haemorrhage. European Journal of Obstetrics Gynecology Reproductive Biology. 1993;48:15\u0026ndash;8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSnegovskikh D, Clebone A, Norwitz E. Anesthetic management of patients with placenta accreta and resuscitation strategies for associated massive hemorrhage. Curr Opin Anaesthesiol. 2011;24:274\u0026ndash;81.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eWeiniger CF, Einav S, Deutsch L, Ginosar Y, Ezra Y, Eid L. Outcomes of prospectively-collected consecutive cases of antenatal-suspected placenta accreta. Int J Obstet Anesth. 2013;22:273\u0026ndash;9.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eWise A, Clark V. Strategies to manage major obstetric haemorrhage. Curr Opin Anaesthesiol. 2008;21:281\u0026ndash;7.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eMarkley JC, Farber MK, Perlman NC, Carusi DA. Neuraxial Anesthesia During Cesarean Delivery for Placenta Previa With Suspected Morbidly Adherent Placenta: A Retrospective Analysis. Anesth Analg. 2018;127:930\u0026ndash;38.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eGyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of bleeding in the late preterm period. Am J Obstet Gynecol. 2018;218:B2-b8.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eBhandari S, Raja EA, Shetty A, Bhattacharya S. Maternal and perinatal consequences of antepartum haemorrhage of unknown origin. BJOG. 2014;121:44\u0026ndash;50. discussion 50 \u0026ndash; 2.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eSchneiderman M, Balayla J. A comparative study of neonatal outcomes in placenta previa versus cesarean for other indication at term. J Matern Fetal Neonatal Med. 2013;26:1121\u0026ndash;7.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eRosenberg T, Pariente G, Sergienko R, Wiznitzer A, Sheiner E. Critical analysis of risk factors and outcome of placenta previa. Arch Gynecol Obstet. 2011;284:47\u0026ndash;51.\u003c/span\u003e \u003c/li\u003e \u003cli\u003e \u003cspan\u003eMastrolia SA, Baumfeld Y, Loverro G, Yohai D, Hershkovitz R, Weintraub AY. Placenta previa associated with severe bleeding leading to hospitalization and delivery: a retrospective population-based cohort study. J Matern Fetal Neonatal Med. 2016;29:3467\u0026ndash;71.\u003c/span\u003e \u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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":"Cesarean delivery, Placenta previa, Antepartum hemorrhage, Preterm, Perinatal outcome","lastPublishedDoi":"10.21203/rs.3.rs-61700/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-61700/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBACKGROUND\u003c/h2\u003e \u003cp\u003ePlacenta previa can be a serious, life-threatening obstetric complication that causes painless but potentially catastrophic bleeding. It is unclear as to whether the frequency of antepartum hemorrhage (APH) relative to the specific gestational week in placenta previa will lead to negative perinatal outcomes. The purpose of the present study was to determine the relationship between APH and gestational week number, and to ascertain the different perinatal outcomes in women with placenta previa.\u003c/p\u003e\u003ch2\u003eMETHODS\u003c/h2\u003e \u003cp\u003eThis was a multi-center, retrospective study in which we enrolled all women with placenta previa between October of 2015 and September of 2018. Patients with placenta previa were divided into two groups: women with APH and women without APH.\u003c/p\u003e\u003ch2\u003eRESULTS\u003c/h2\u003e \u003cp\u003eA total of 247 patients were included in this study: 121 women with APH and 126 women without. The incidence of APH was 49.0% (121/247). The mean bleeding frequency was 2.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD), with the majority having experienced a one-time bleeding episode (36.4%, 44/121), followed by 26.4% with 2 episodes (32/121), and 23.1% with 3 (28/121). The APH was distinct in every gestational-week category, with bleeding occurring at 31.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 weeks, ranging from 24 to 37 gestational weeks. The incidence of bleeding varied from 2.6\u0026ndash;14.6%, with the highest incidence at 32 gestational weeks. Patients categorized as having complete placental coverage included a greater number of women experiencing bleeding than women who did not bleed (72.9% vs 47.4%, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating that a complete placenta was an independent risk factor for APH (odds rations [OR], 4.17; 95% confidence interval [CI], 1.805\u0026ndash;9.634). In addition, although APH did not augment the rates of hysterectomy (6.6% vs 7.1%, P\u0026thinsp;=\u0026thinsp;0.869), it was associated with critical neonatal outcomes that included lower weight, lower Apgar score at 1 minute, preterm age, and more frequent neonatal intensive care unit admissions (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eCONCLUSIONS\u003c/h2\u003e \u003cp\u003eThe gestational week and frequency of each APH varied in patients with placenta previa and might result in an increase in adverse maternal and neonatal outcomes. The 32nd gestational week appeared to be the most precarious time\u0026mdash;exhibiting the highest incidence of bleeding\u0026mdash;and we consider complete placenta previa to be an independent risk factor for APH.\u003c/p\u003e","manuscriptTitle":"Influence of antepartum hemorrhage on placenta previa: A multi-center, retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2020-08-21 16:19:24","doi":"10.21203/rs.3.rs-61700/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":"b29e7e76-2d02-415c-be70-f9ff5e1e70dd","owner":[],"postedDate":"August 21st, 2020","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":336581,"name":"Maternal \u0026 Fetal Medicine"}],"tags":[],"updatedAt":"2021-12-15T08:34:26+00:00","versionOfRecord":{"articleIdentity":"rs-61700","link":"https://doi.org/10.31083/j.ceog4806226","journal":{"identity":"clinical-and-experimental-obstetrics-and-gynecology","isVorOnly":true,"title":"Clinical and Experimental Obstetrics \u0026 Gynecology"},"publishedOn":"2021-01-01 08:34:26","publishedOnDateReadable":"January 1st, 2021"},"versionCreatedAt":"2020-08-21 16:19:24","video":"","vorDoi":"10.31083/j.ceog4806226","vorDoiUrl":"https://doi.org/10.31083/j.ceog4806226","workflowStages":[]},"version":"v1","identity":"rs-61700","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-61700","identity":"rs-61700","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}