The association between fetal head malrotation and labor analgesia: a propensity score-matched analysis

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Previous studies have suggested an association between malrotation and labor analgesia, but this remains controversial. This study aimed to clarify whether malrotation increases with the use of labor analgesia. Methods This retrospective cohort study using propensity score matching. Medical records from January 2020 to January 2023 were reviewed. The study subjects were full-term pregnant women with singleton cephalic fetuses whose cervixes were fully dilated. The group without labor analgesia (Group C) was matched with the labor analgesia group (Group A) by propensity score matching. The primary outcome was the occurrence of malrotation. Secondary outcomes included rates of normal vaginal delivery, instrumental delivery, cesarean section, and success rate of attempted manual rotation. Pearson’s chi-square test was used to assess the association between the use of labor analgesia and outcomes. Results During the study period, 3868 women were included, 1164 cases were excluded due to the exclusion criteria, and 971 cases were further excluded due to missing data. Of 1735 eligible women, 88.4% received labor analgesia. After propensity score matching, 804 women were included, of whom 75% received labor analgesia (Group A) and 25% did not (Group C). The rate of malrotation was significantly higher in Group A compared to that in Group C (11.6% vs. 6.5%, p = 0.03). The rate of instrumental delivery was significantly higher in Group A (25.7% vs. 14.9%, p = 0.001). The distribution of the instrumental deliveries in Group A was as follows: Naegele forceps delivery was used in 87.1% of the cases, Kielland forceps in 5.2%, and vacuum extraction in 7.7%. There was no significant difference in the rate of vaginal delivery. Manual rotation was attempted in 84.3% of malrotation cases in Group A with a 64.4% success rate, with no significant difference of the success rate between the two groups. Conclusions Labor analgesia is associated with an increased rate of malrotation and instrumental delivery. However, it does not seem to decrease the rate of vaginal delivery, given the high attempt and success rates of manual rotation and the availability of Kielland forceps delivery. Fetal head malrotation Kielland forceps delivery Labor analgesia Manual rotation Propensity score matching Figures Figure 1 Figure 2 Background Fetal head malrotation, defined as a fetal head other than the occiput anterior position, is associated with a range of abnormal deliveries and often requires medical intervention. Malrotation is also associated with arrested and prolonged labor, leading to the need for instrumental delivery and increasing the rate of cesarean delivery.[ 1 ][ 2 ] Malrotation also increases the risk of chorioamnionitis, laceration of the perineum, postpartum hemorrhage, postpartum urinary disorder, postpartum infection, and all sorts of perinatal complications.[ 3 – 5 ] These complications can manifest as birth injuries to both the mother and baby; therefore, understanding and managing fetal head malposition are essential for handling the course of labor. Many efforts have been made to reduce the rate of malrotation at the time of delivery by changing maternal positions, including, hand and knee positions with or without pelvic rocking, but these have proven unsuccessful in reducing persistent occiput posterior.[ 6 ][ 7 ] Considering these studies, the mainstream methods to fix malrotation are manual rotation and rotational forceps delivery, such as Kielland forceps delivery. The use of labor analgesia is a common practice to alleviate pain during labor. Labor analgesia is used in more than 70% of the women in the US.[ 8 ] The potential relationship between the use of labor analgesia and the occurrence of malrotation is uncertain,[ 9 ][ 10 ] and its potential impact on subsequent birth outcomes remains to be investigated. Thus, this study aimed to clarify whether the use of labor analgesia is associated with an increased incidence of malrotation by matching maternal characteristics and interventions during delivery. Methods Study design and ethics This retrospective cohort study with propensity score matching (PSM) was conducted at the Juntendo University Hospital. This study was approved by the Ethics Committee of Juntendo University Hospital (E23-0351) in accordance with the Declaration of Helsinki. Owing to the nature of the study, the need for individual informed consent was waived. Patient recruitment Medical records from January 2020 to January 2023 were reviewed. Delivery at our institution encompassed 1193, 1266, and 1265 cases in 2020, 2021, and 2022, respectively, and vaginal delivery accounted for approximately 1000 cases per year, including 85–90% of the women choosing labor analgesia. To match enough pairs with the labor analgesia group and the non-labor analgesia group, and to ensure the accuracy of subsequent analysis, data were collected for three years. Intrapartum data including the use of labor analgesia, implementation of labor induction or augmentation, mode of delivery, and success rate of the attempted manual rotation were collected. Maternal characteristics, including age at delivery, parity, gestational age, stature and weight before pregnancy and at delivery, were collected. In addition, the weight and head circumference at birth were recorded. The inclusion criteria encompassed full-term pregnancy with a singleton cephalic fetus whose cervix was fully dilated. Exclusion criteria were maternal age 50 years, fetal abnormality, emergency cesarean delivery with indications other than labor arrest due to malrotation, stillbirth, and delivery out of medical facilities. The primary outcome was the occurrence of malrotation. Mode of delivery and the success rate of attempted manual rotation were considered secondary outcomes. Cases categorized as fetal head malposition in our study In our study, malrotation was diagnosed after the cervix was fully dilated by pelvic examination, according to the inclusion criteria. We defined malrotation as the sagittal suture and fontanels being aligned 45 degrees to 180 degrees from the longitudinal direction of the maternal pelvis. Occiput posterior is diagnosed when the posterior fontanel is toward the sacrum and the anterior fontanel is easily felt with the head deflexed. Occiput transverse, including both transverse position and arrest, is diagnosed when the sagittal suture and fontanels are aligned 0 degrees to 15 degrees from the transverse plane of the pelvis. Labor Management Anesthesiologists chose labor analgesia, combined spinal-epidural anesthesia (CSEA) or dural puncture epidural (DPE), depending on the prospect of delivery and the level of pain in the mother. Maternal characteristics were considered for selection as supplemental information. Approximately 90% of deliveries were selected for DPE. The protocols for CSEA and DPE were similar to those used in Okahara’s study, which was conducted at our institution.[ 11 ] An epidural catheter was placed at the time of maternal request when no contraindications were present. Additional boluses of anesthetics were administered if needed, and the catheter was replaced if analgesia failed to prevent pain. Additional amount of anesthesia was not controlled, considering the pelvic examination and malrotation. Manual rotation was only conducted when malrotation was seen after the cervix was fully opened, except in a few cases. Kielland forceps were utilized when malrotation was present, even after manual rotation failed. Labor was augmented using oxytocin when labor protraction occurred, typically when cervical dilation did not change for an hour after the cervix dilated 6 cm or more. Statistical analysis Enrolled women who met the inclusion criteria were divided into two groups. The group without labor analgesia was considered the control group (Group C) and was matched with the labor analgesia group (Group A) by PSM. The intergroup difference was compared by Student’s t-test or Wilcoxon rank sum test for continuous variables depending on their normality and the Pearson’s chi-square test or Fisher’s exact test for categorical data. PSM analysis was used to control for potential confounders. Patients who received labor analgesia were matched 3:1 (patients who received labor analgesia: patients without labor analgesia) using their propensity score. Variables for PSM were chosen as follows: (1) potential baseline differences between groups with a P value less than 0.10, (2) potentially relevant variables according to previous studies and clinical importance, and (3) missing data less than 10%. As a result, the baseline variables of the maternal age at delivery, stature, and weight of the mother before pregnancy; weight of the mother at delivery; parity status; gestational age at delivery; weight and head circumference of the baby; and use of labor induction or augmentation were used for PSM. The standardized mean difference was used to assess the balance of baseline covariates between the treatment groups in the matched and unmatched samples. A standardized mean difference of more than 0.1 and a 2-sided P value of less than 0.05 indicated a significant imbalance in the baseline covariate. PSM was conducted using the nearest-neighbor method with a caliper = 0.20, without replacement. After matching, Pearson’s chi-square test was used to assess the association between labor analgesia and primary and secondary outcomes. P values of less than 0.05 indicated statistical significance. Statistical analysis was performed using SAS version 9.4 (SAS Institute) and JMP software. Results Maternal characteristics Between January 2020 and January 2023, 3868 women were screened. Of these, 2704 met the inclusion criteria and 1735 women without missing data were enrolled in the study. Among the 1735 women, 1534 (88.4%) received labor analgesia and 201 (11.6%) did not. After 1:3 ratio PSM, 804 women remained in the analysis, of whom 603 (75%) received labor analgesia and 201 (25%) did not [Fig. 1 ]. The baseline variables were balanced between Groups C and A using PSM [Table 1]. In making matched pairs of Groups C and A, the implementation of labor induction and augmentation had the biggest difference between the two groups; hence, they needed to be balanced [Fig. 2 ]. Association of labor analgesia and the outcomes in women before propensity score matching Before PSM, the rate of malrotation was 15.6% in the labor analgesia group. The rates of instrumental and vaginal deliveries were 33.9% and 98.9%, respectively. The distribution of the instrumental deliveries in the labor anesthesia group was: Naegele forceps delivery was used in 86.0% of the cases, Kielland forceps in 7.3%, and vacuum extraction in 6.7%. Manual rotation was attempted in 85.0% of the cases with malrotation in the labor analgesia group, and 62.7% succeeded [Table 2]. Association of labor analgesia and the outcomes in matched women In matched women, the rate of malrotation was significantly higher in Group A compared to that in Group C (11.6% vs. 6.5%, p = 0.03). The rate of instrumental delivery was significantly higher in Group A compared to that in Group C (25.7% vs. 14.9%, p = 0.001). Contrastingly, there was no significant difference in the rate of vaginal delivery (99.9% vs. 100%, p = 0.51). The distribution of the instrumental deliveries in Group A was: Naegele forceps delivery was used in 87.1% of the cases, Kielland forceps in 5.2%, and vacuum extraction in 7.7%. The distribution of the instrumental deliveries in Group C group was: Naegele forceps delivery was used in 93.3% of the cases, Kielland forceps delivery in 3.3%, and vacuum extraction in 3.3%. Manual rotation was attempted in 84.3% of the cases with malrotation in Group A, with a 64.4% success rate, whereas 84.6% cases were attempted in Group C, with a 72.7% success rate [Table 3]. No significant difference was observed in the success rate of manual rotation between Groups A and C. Structured Discussion/Comment 1. Principal Findings The results of this single-center retrospective cohort study showed that labor analgesia was associated with the risk of malrotation, even after balancing the baseline variables by PSM. The biggest factor that needed to be fixed when making matched pairs was implementation of labor augmentation. In addition, our study showed a significantly higher rate of instrumental delivery in the labor anesthesia group than in the group without labor anesthesia, albeit with no decrease in the rate of vaginal delivery due to the high success rate of Kielland forceps delivery and manual rotation. 2. Results In published studies, the risks of malrotation include nulliparity, maternal age > 35 years, short maternal stature, induction and augmentation of labor, gestational age > 41 weeks, high body mass index, fetal macrosomia, and anterior placental position.[ 2 – 4 ][ 12 – 15 ] In our study, we performed PSM analyses to balance the variables of maternal and neonatal background, including the aforementioned known risk factors except for the position of the placenta, between the labor and non-labor analgesia groups. To the best of our knowledge, this is the first study to compare the occurrence of malrotation using PSM (MEDLINE; March 1980 to April 2024; search terms: ‘malrotation,’ ‘labor anesthesia,’ and ‘propensity score matching’). Among the eligible patients, missing data were observed in 971 cases. Trends in the missing data had no specific attributes and were unlikely to affect the results. 3. Clinical Implications Two theories have been proposed to explain the association between labor analgesia and malrotation. As the implementation of labor augmentation was the biggest factor fixed, it might mean that the contraction of the uterus was weak. It is possible that weak contraction or contraction agents themselves may lead to malrotation. To support this speculation, a study reported that rhythmic and synchronic contractions are important for normal vaginal delivery.[ 16 ] Second, labor analgesia blocks the motor and sensory nerves of the pelvis.[ 17 ][ 18 ] This block leads to the relaxation of the pelvic floor muscles and expansion of the vagina, which leads to the descent of the fetal head without appropriate rotation.[ 19 ] Two factors are important in handling malrotation for the success of safe vaginal delivery: high attempt and success rates of manual rotation and the availability of Kielland forceps delivery. Although our study showed that labor analgesia was associated with the risk of malrotation and the risk of instrumental delivery, forceps delivery itself does not significantly increase the complications of fourth-degree perineal and cervical lacerations in our method.[ 20 ] However, in cases with malrotation, the complications of fourth-degree perineal and cervical lacerations are considerably higher than those in cases without malrotation.[ 21 ] By diagnosing malrotation and succeeding in manual rotation, it decreases occiput posterior at birth, cesarean delivery rate,[ 22 ] instrumental delivery rate and fourth-degree perineal laceration, and also shortens the second stage of labor.[ 23 – 25 ] Thus, an accurate pelvic examination is essential to diagnose malrotation.[ 26 ] The majority of facilities in our country choose vacuum extraction rather than forceps delivery for instrumental delivery, even more so for Kielland forceps delivery[ 27 ] due to the reported adverse outcomes and the lack of trainers.[ 28 ] However, recent studies have shown the safety and effectiveness of Kielland forceps in handling malrotation[ 29 ]; due to the achievement of a high vaginal delivery rate without increasing maternal and fetal morbidity,[ 28 ] as well as a small failure rate,[ 29 ] Kielland forceps are re-emerging as useful instruments in modern obstetrics. Thus, manual rotation and Kielland forceps are essential to prevent an increase in the cesarean rate in cases with malrotation. On the other hand, it is unknown whether manual rotation or Kielland forceps is better for maternal and neonatal outcomes outcome and for reducing the cesarean rate. One report showed that the use of Kielland forceps was associated with shoulder dystocia compared to manual rotation.[ 30 ] Taking this report into account, in a case with malrotation, it might be better to try manual rotation first, followed by Kielland forceps delivery for the failed cases, as is the method at our facility. 4. Research Implications In our study, we did not divide the women into CSEA and DPE groups, which might have had an impact on the occurrence of malrotation due to the difference in the contraction of the uterus.[ 31 ] In addition, we only included deliveries following full dilation of the cervixes. However, there were a few cases in which manual rotation was attempted before full dilation of the cervix, suggesting that the rate of malrotation was higher. The effect of prophylactic manual rotation at the early second stage of labor on decreasing operative delivery remains controversial.[ 32 ][ 33 ] These studies suggest that the best time for malrotation diagnosis and manual rotation enforcement is in the latter part of the second stage of labor. Evidence to choose CSEA or DPE and the establishment of a method and timing for manual rotation are needed. This study highlights the importance of education on delivery assistance. Our facility uses videos of Kielland forceps delivery to educate novice obstetricians,[ 34 ] which is one of our greatest strengths in handling the highest numbers of deliveries with labor analgesia in our country.[ 35 ] In the era of the increasing use of labor analgesia in our country, obtaining the skill of Kielland forceps use would be an essential option. Training for a safe operative birth is a key priority in obstetrics.[ 34 ] As in the Royal College of Obstetricians and Gynecologists Operative Birth Simulation Training (ROBuST) course in the UK, the Kielland forceps technique is being handed down using the training program.[ 36 ] As a result of this education, Kielland forceps delivery is widely used across the whole country. 5. Strength and Limitations The greatest strength of our study is that it is the first to determine the association between malrotation and the use of labor analgesia using PSM. This matching was conducted to assess the effect of labor analgesia on malrotation, excluding other risks that might affect malrotation. Additionally, this study was conducted at a single center, which means that the management of delivery was homogeneous. This study had some limitations. First, as in all observational studies, confounders could be a concern, despite the statistical effort made. Therefore, the clinical implications of our study should be interpreted with caution, as we may need to measure unknown factors associated with malrotation. Second, this observational study was conducted at our single institution. The analgesic effect of epidural anesthesia with spinal anesthesia is more significant compared with epidural anesthesia alone. Applying our results to all parturient might introduce some bias. Conclusion We conclude that labor analgesia is associated with an increased rate of malrotation and instrumental delivery. However, labor analgesia does not seem to affect the rate of vaginal delivery, with a high attempt and success rate of manual rotation and the option of Kielland forceps delivery. Abbreviations PSM: Propensity Score Matching CSEA: Combined Spinal-Epidural Anesthesia DPE: Dural Puncture Epidural Declarations Ethics approval and consent to participate This retrospective cohort study was approved by the Ethics Committee of Juntendo University Hospital (E23-0351) in accordance with the Declaration of Helsinki. Due to the nature of the study, the need for informed consent to the individual was waived. Consent for publication Not applicable Availability of data and materials The data that support the findings of this study are available from the corresponding author s upon reasonable request. Competing interests All authors declare no conflict of interest with regards to this article. Funding No funds, grants, or other support was received Authors' contributions NT contributed to the acquisition and analysis of the data, interpretation of the results, and drafted the original manuscript. JT contributed to the study conceptualization and interpretation of the results. JT and AI critically revised the manuscript and supervised the conduct of the study. SU and SN contributed to the analysis of the data and interpretation of the result and critically revised the manuscript. All authors reviewed the draft manuscript and approved the final version of manuscript to be published. Acknowledgements We thank Editage (https://www.editage.jp) for editing this manuscript. References Fitzpatrick M, McQuillan K, O'Herlihy C. Influence of persistent occiput posterior position on delivery outcome. Obstet Gynecol. 2001;98(6):1027-1031. doi:10.1016/s0029-7844(01)01600-3 Sizer AR, Nirmal DM. Occiput posterior position: associated factors and obstetric outcome in nulliparas. 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Dural puncture epidural technique improves labor analgesia quality with fewer side effects compared with epidural and combined spinal epidural techniques: A randomized clinical trial. Anesth Analg . 2017;124(2):560-569. doi:10.1213/ANE.0000000000001798 Blanc J, Castel P, Mauviel F, et al. Prophylactic manual rotation of occiput posterior and transverse positions to decrease operative delivery: the PROPOP randomized clinical trial. Am J Obstet Gynecol . 2021;225(4):444.e1-444.e8. doi:10.1016/j.ajog.2021.05.020 Verhaeghe C, Corroenne R, Spiers A, et al. Delivery mode after manual rotation of occiput posterior fetal positions: A randomized controlled trial. Obstet Gynecol . 2021;137(6):999-1006. doi:10.1097/AOG.0000000000004386 Takeda J, Makino S, Itakura A, Takeda S. Technique of rotational forceps delivery using UTokyo Kielland Forceps. Hypertens Res Pregnancy . 2017;5(1):26-27. doi:10.14390/jsshp.HRP2017-005 Takeda S. New Assessment of Fetal Descent and Forceps Delivery . Springer; 2018. The health academy; 2024, February 6. https://healthacademy.lancsteachinghospitals.nhs.uk/courses/surgical-simulation-training/robust-rcog-franchised/ Tables Tables are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files BMC.table1.xlsx BMC.table2.xlsx BMC.table3.xlsx Cite Share Download PDF Status: Published Journal Publication published 29 Dec, 2025 Read the published version in BMC Pregnancy and Childbirth → Version 1 posted Editorial decision: Revision requested 16 Apr, 2025 Reviews received at journal 04 Apr, 2025 Reviewers agreed at journal 26 Dec, 2024 Reviews received at journal 10 Dec, 2024 Reviewers agreed at journal 03 Dec, 2024 Reviewers invited by journal 01 Dec, 2024 Editor invited by journal 31 Oct, 2024 Editor assigned by journal 30 Oct, 2024 Submission checks completed at journal 30 Oct, 2024 First submitted to journal 29 Oct, 2024 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. 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Takeda","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIiWNgGAWjYBACxgYGZgYGNgY5IAMEmCHCEvi0tEG0GAO1gHQRoQWoGqwlsYEBWQs+wDy/+bHBhzK79OYZuccffNxhLcfAfvgBg+UOfA5jM06ccS45t3FGXmLjzDPpxgw8aQYMkmfw+sX4MG8bM1BLjmEzb9thoAtzGBgk2/BpYf98+G9bfTojSMtfkBb+N4S08BgnM7YdTgBrYQRpkSBoS06xYc+544aNPW8MZ/a2pRuzSTwzOIDPL4bNxzdL/CirljdszzH48LPNWo6fP/nhY0k8IWbYgM5gA+LDkg3YFEOAPAYD7NyPeLSMglEwCkbBiAMAgJ9QEHYzRoYAAAAASUVORK5CYII=","orcid":"","institution":"Juntendo University","correspondingAuthor":true,"prefix":"","firstName":"Jun","middleName":"","lastName":"Takeda","suffix":""},{"id":376119109,"identity":"f3d667a5-5ad9-426d-826b-30db60b80517","order_by":2,"name":"Saki Uchiyama","email":"","orcid":"","institution":"Juntendo University","correspondingAuthor":false,"prefix":"","firstName":"Saki","middleName":"","lastName":"Uchiyama","suffix":""},{"id":376119110,"identity":"06a421ed-e420-4975-9f0e-19632eef2dfd","order_by":3,"name":"Shuko Nojiri","email":"","orcid":"","institution":"Juntendo University","correspondingAuthor":false,"prefix":"","firstName":"Shuko","middleName":"","lastName":"Nojiri","suffix":""},{"id":376119111,"identity":"908d8cb3-a2a3-4a6e-8636-e2423868e941","order_by":4,"name":"Atsuo Itakura","email":"","orcid":"","institution":"Juntendo University","correspondingAuthor":false,"prefix":"","firstName":"Atsuo","middleName":"","lastName":"Itakura","suffix":""}],"badges":[],"createdAt":"2024-10-29 10:53:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5353654/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5353654/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12884-025-08431-0","type":"published","date":"2025-12-29T15:57:48+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":69442726,"identity":"a2f11a6f-ddb0-4fb2-8ba6-c441af5a68ef","added_by":"auto","created_at":"2024-11-20 11:28:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44629,"visible":true,"origin":"","legend":"\u003cp\u003eConsort diagram of eligible women for cohort\u003c/p\u003e","description":"","filename":"Figure11.png","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/5607560ee94a5fb8778f02ff.png"},{"id":69442727,"identity":"ddf5b9b3-9a41-4e52-a5c0-7ca32f47a37a","added_by":"auto","created_at":"2024-11-20 11:28:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":36617,"visible":true,"origin":"","legend":"\u003cp\u003eStandardized Mean Differences of all and matched women\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/ee87157e9dd1b4bba4b525e9.png"},{"id":99545278,"identity":"659f4448-a65b-40a2-a987-15e06dace05a","added_by":"auto","created_at":"2026-01-05 16:05:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":863057,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/ff825d50-01b8-41ec-a1a0-d4455d500bfe.pdf"},{"id":69441174,"identity":"647afa8e-4997-4f1b-b3f4-dd20f8cc823a","added_by":"auto","created_at":"2024-11-20 11:20:42","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":10954,"visible":true,"origin":"","legend":"","description":"","filename":"BMC.table1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/94f90921b86c92f69db3a070.xlsx"},{"id":69441172,"identity":"98191f87-18a4-4c81-b386-c5685614d51c","added_by":"auto","created_at":"2024-11-20 11:20:42","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":10271,"visible":true,"origin":"","legend":"","description":"","filename":"BMC.table2.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/219e27b6413fc6f4d02116a6.xlsx"},{"id":69441175,"identity":"d122ea92-82a7-49ea-9713-d7e95fbc7156","added_by":"auto","created_at":"2024-11-20 11:20:42","extension":"xlsx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":10959,"visible":true,"origin":"","legend":"","description":"","filename":"BMC.table3.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-5353654/v1/c34f7177d868b6f91f9cb01c.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"The association between fetal head malrotation and labor analgesia: a propensity score-matched analysis","fulltext":[{"header":"Background","content":"\u003cp\u003eFetal head malrotation, defined as a fetal head other than the occiput anterior position, is associated with a range of abnormal deliveries and often requires medical intervention. Malrotation is also associated with arrested and prolonged labor, leading to the need for instrumental delivery and increasing the rate of cesarean delivery.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e][\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] Malrotation also increases the risk of chorioamnionitis, laceration of the perineum, postpartum hemorrhage, postpartum urinary disorder, postpartum infection, and all sorts of perinatal complications.[\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] These complications can manifest as birth injuries to both the mother and baby; therefore, understanding and managing fetal head malposition are essential for handling the course of labor. Many efforts have been made to reduce the rate of malrotation at the time of delivery by changing maternal positions, including, hand and knee positions with or without pelvic rocking, but these have proven unsuccessful in reducing persistent occiput posterior.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e][\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] Considering these studies, the mainstream methods to fix malrotation are manual rotation and rotational forceps delivery, such as Kielland forceps delivery.\u003c/p\u003e \u003cp\u003eThe use of labor analgesia is a common practice to alleviate pain during labor. Labor analgesia is used in more than 70% of the women in the US.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] The potential relationship between the use of labor analgesia and the occurrence of malrotation is uncertain,[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e][\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and its potential impact on subsequent birth outcomes remains to be investigated. Thus, this study aimed to clarify whether the use of labor analgesia is associated with an increased incidence of malrotation by matching maternal characteristics and interventions during delivery.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and ethics\u003c/h2\u003e \u003cp\u003eThis retrospective cohort study with propensity score matching (PSM) was conducted at the Juntendo University Hospital. This study was approved by the Ethics Committee of Juntendo University Hospital (E23-0351) in accordance with the Declaration of Helsinki. Owing to the nature of the study, the need for individual informed consent was waived.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePatient recruitment\u003c/h3\u003e\n\u003cp\u003eMedical records from January 2020 to January 2023 were reviewed. Delivery at our institution encompassed 1193, 1266, and 1265 cases in 2020, 2021, and 2022, respectively, and vaginal delivery accounted for approximately 1000 cases per year, including 85\u0026ndash;90% of the women choosing labor analgesia. To match enough pairs with the labor analgesia group and the non-labor analgesia group, and to ensure the accuracy of subsequent analysis, data were collected for three years. Intrapartum data including the use of labor analgesia, implementation of labor induction or augmentation, mode of delivery, and success rate of the attempted manual rotation were collected. Maternal characteristics, including age at delivery, parity, gestational age, stature and weight before pregnancy and at delivery, were collected. In addition, the weight and head circumference at birth were recorded. The inclusion criteria encompassed full-term pregnancy with a singleton cephalic fetus whose cervix was fully dilated. Exclusion criteria were maternal age\u0026thinsp;\u0026lt;\u0026thinsp;18 or \u0026gt;\u0026thinsp;50 years, fetal abnormality, emergency cesarean delivery with indications other than labor arrest due to malrotation, stillbirth, and delivery out of medical facilities.\u003c/p\u003e \u003cp\u003eThe primary outcome was the occurrence of malrotation. Mode of delivery and the success rate of attempted manual rotation were considered secondary outcomes.\u003c/p\u003e\n\u003ch3\u003eCases categorized as fetal head malposition in our study\u003c/h3\u003e\n\u003cp\u003eIn our study, malrotation was diagnosed after the cervix was fully dilated by pelvic examination, according to the inclusion criteria. We defined malrotation as the sagittal suture and fontanels being aligned 45 degrees to 180 degrees from the longitudinal direction of the maternal pelvis. Occiput posterior is diagnosed when the posterior fontanel is toward the sacrum and the anterior fontanel is easily felt with the head deflexed. Occiput transverse, including both transverse position and arrest, is diagnosed when the sagittal suture and fontanels are aligned 0 degrees to 15 degrees from the transverse plane of the pelvis.\u003c/p\u003e\n\u003ch3\u003eLabor Management\u003c/h3\u003e\n\u003cp\u003eAnesthesiologists chose labor analgesia, combined spinal-epidural anesthesia (CSEA) or dural puncture epidural (DPE), depending on the prospect of delivery and the level of pain in the mother. Maternal characteristics were considered for selection as supplemental information. Approximately 90% of deliveries were selected for DPE. The protocols for CSEA and DPE were similar to those used in Okahara\u0026rsquo;s study, which was conducted at our institution.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] An epidural catheter was placed at the time of maternal request when no contraindications were present. Additional boluses of anesthetics were administered if needed, and the catheter was replaced if analgesia failed to prevent pain. Additional amount of anesthesia was not controlled, considering the pelvic examination and malrotation. Manual rotation was only conducted when malrotation was seen after the cervix was fully opened, except in a few cases. Kielland forceps were utilized when malrotation was present, even after manual rotation failed. Labor was augmented using oxytocin when labor protraction occurred, typically when cervical dilation did not change for an hour after the cervix dilated 6 cm or more.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eEnrolled women who met the inclusion criteria were divided into two groups. The group without labor analgesia was considered the control group (Group C) and was matched with the labor analgesia group (Group A) by PSM. The intergroup difference was compared by Student\u0026rsquo;s t-test or Wilcoxon rank sum test for continuous variables depending on their normality and the Pearson\u0026rsquo;s chi-square test or Fisher\u0026rsquo;s exact test for categorical data. PSM analysis was used to control for potential confounders. Patients who received labor analgesia were matched 3:1 (patients who received labor analgesia: patients without labor analgesia) using their propensity score. Variables for PSM were chosen as follows: (1) potential baseline differences between groups with a P value less than 0.10, (2) potentially relevant variables according to previous studies and clinical importance, and (3) missing data less than 10%. As a result, the baseline variables of the maternal age at delivery, stature, and weight of the mother before pregnancy; weight of the mother at delivery; parity status; gestational age at delivery; weight and head circumference of the baby; and use of labor induction or augmentation were used for PSM. The standardized mean difference was used to assess the balance of baseline covariates between the treatment groups in the matched and unmatched samples. A standardized mean difference of more than 0.1 and a 2-sided P value of less than 0.05 indicated a significant imbalance in the baseline covariate.\u003c/p\u003e \u003cp\u003ePSM was conducted using the nearest-neighbor method with a caliper\u0026thinsp;=\u0026thinsp;0.20, without replacement. After matching, Pearson\u0026rsquo;s chi-square test was used to assess the association between labor analgesia and primary and secondary outcomes. P values of less than 0.05 indicated statistical significance. Statistical analysis was performed using SAS version 9.4 (SAS Institute) and JMP software.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eMaternal characteristics\u003c/h2\u003e \u003cp\u003eBetween January 2020 and January 2023, 3868 women were screened. Of these, 2704 met the inclusion criteria and 1735 women without missing data were enrolled in the study. Among the 1735 women, 1534 (88.4%) received labor analgesia and 201 (11.6%) did not. After 1:3 ratio PSM, 804 women remained in the analysis, of whom 603 (75%) received labor analgesia and 201 (25%) did not [Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe baseline variables were balanced between Groups C and A using PSM [Table\u0026nbsp;1]. In making matched pairs of Groups C and A, the implementation of labor induction and augmentation had the biggest difference between the two groups; hence, they needed to be balanced [Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAssociation of labor analgesia and the outcomes in women before propensity score matching\u003c/h3\u003e\n\u003cp\u003eBefore PSM, the rate of malrotation was 15.6% in the labor analgesia group. The rates of instrumental and vaginal deliveries were 33.9% and 98.9%, respectively. The distribution of the instrumental deliveries in the labor anesthesia group was: Naegele forceps delivery was used in 86.0% of the cases, Kielland forceps in 7.3%, and vacuum extraction in 6.7%. Manual rotation was attempted in 85.0% of the cases with malrotation in the labor analgesia group, and 62.7% succeeded [Table\u0026nbsp;2].\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eAssociation of labor analgesia and the outcomes in matched women\u003c/h2\u003e \u003cp\u003eIn matched women, the rate of malrotation was significantly higher in Group A compared to that in Group C (11.6% vs. 6.5%, p = 0.03). The rate of instrumental delivery was significantly higher in Group A compared to that in Group C (25.7% vs. 14.9%, p = 0.001). Contrastingly, there was no significant difference in the rate of vaginal delivery (99.9% vs. 100%, p = 0.51).\u003c/p\u003e \u003cp\u003eThe distribution of the instrumental deliveries in Group A was: Naegele forceps delivery was used in 87.1% of the cases, Kielland forceps in 5.2%, and vacuum extraction in 7.7%. The distribution of the instrumental deliveries in Group C group was: Naegele forceps delivery was used in 93.3% of the cases, Kielland forceps delivery in 3.3%, and vacuum extraction in 3.3%.\u003c/p\u003e \u003cp\u003eManual rotation was attempted in 84.3% of the cases with malrotation in Group A, with a 64.4% success rate, whereas 84.6% cases were attempted in Group C, with a 72.7% success rate [Table\u0026nbsp;3]. No significant difference was observed in the success rate of manual rotation between Groups A and C.\u003c/p\u003e \u003c/div\u003e "},{"header":"Structured Discussion/Comment","content":"\u003ch2\u003e1. Principal Findings\u003c/h2\u003e\u003cp\u003eThe results of this single-center retrospective cohort study showed that labor analgesia was associated with the risk of malrotation, even after balancing the baseline variables by PSM. The biggest factor that needed to be fixed when making matched pairs was implementation of labor augmentation. In addition, our study showed a significantly higher rate of instrumental delivery in the labor anesthesia group than in the group without labor anesthesia, albeit with no decrease in the rate of vaginal delivery due to the high success rate of Kielland forceps delivery and manual rotation.\u003c/p\u003e\u003ch2\u003e2. Results\u003c/h2\u003e\u003cp\u003eIn published studies, the risks of malrotation include nulliparity, maternal age \u0026gt; 35 years, short maternal stature, induction and augmentation of labor, gestational age \u0026gt; 41 weeks, high body mass index, fetal macrosomia, and anterior placental position.[\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e–\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e][\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e–\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] In our study, we performed PSM analyses to balance the variables of maternal and neonatal background, including the aforementioned known risk factors except for the position of the placenta, between the labor and non-labor analgesia groups. To the best of our knowledge, this is the first study to compare the occurrence of malrotation using PSM (MEDLINE; March 1980 to April 2024; search terms: ‘malrotation,’ ‘labor anesthesia,’ and ‘propensity score matching’). Among the eligible patients, missing data were observed in 971 cases. Trends in the missing data had no specific attributes and were unlikely to affect the results.\u003c/p\u003e\u003ch2\u003e3. Clinical Implications\u003c/h2\u003e\u003cp\u003eTwo theories have been proposed to explain the association between labor analgesia and malrotation. As the implementation of labor augmentation was the biggest factor fixed, it might mean that the contraction of the uterus was weak. It is possible that weak contraction or contraction agents themselves may lead to malrotation. To support this speculation, a study reported that rhythmic and synchronic contractions are important for normal vaginal delivery.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] Second, labor analgesia blocks the motor and sensory nerves of the pelvis.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e][\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] This block leads to the relaxation of the pelvic floor muscles and expansion of the vagina, which leads to the descent of the fetal head without appropriate rotation.[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eTwo factors are important in handling malrotation for the success of safe vaginal delivery: high attempt and success rates of manual rotation and the availability of Kielland forceps delivery. Although our study showed that labor analgesia was associated with the risk of malrotation and the risk of instrumental delivery, forceps delivery itself does not significantly increase the complications of fourth-degree perineal and cervical lacerations in our method.[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] However, in cases with malrotation, the complications of fourth-degree perineal and cervical lacerations are considerably higher than those in cases without malrotation.[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] By diagnosing malrotation and succeeding in manual rotation, it decreases occiput posterior at birth, cesarean delivery rate,[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] instrumental delivery rate and fourth-degree perineal laceration, and also shortens the second stage of labor.[\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e–\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] Thus, an accurate pelvic examination is essential to diagnose malrotation.[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] The majority of facilities in our country choose vacuum extraction rather than forceps delivery for instrumental delivery, even more so for Kielland forceps delivery[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] due to the reported adverse outcomes and the lack of trainers.[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] However, recent studies have shown the safety and effectiveness of Kielland forceps in handling malrotation[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]; due to the achievement of a high vaginal delivery rate without increasing maternal and fetal morbidity,[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] as well as a small failure rate,[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] Kielland forceps are re-emerging as useful instruments in modern obstetrics. Thus, manual rotation and Kielland forceps are essential to prevent an increase in the cesarean rate in cases with malrotation.\u003c/p\u003e\u003cp\u003eOn the other hand, it is unknown whether manual rotation or Kielland forceps is better for maternal and neonatal outcomes outcome and for reducing the cesarean rate. One report showed that the use of Kielland forceps was associated with shoulder dystocia compared to manual rotation.[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] Taking this report into account, in a case with malrotation, it might be better to try manual rotation first, followed by Kielland forceps delivery for the failed cases, as is the method at our facility.\u003c/p\u003e\u003ch2\u003e4. Research Implications\u003c/h2\u003e\u003cp\u003eIn our study, we did not divide the women into CSEA and DPE groups, which might have had an impact on the occurrence of malrotation due to the difference in the contraction of the uterus.[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] In addition, we only included deliveries following full dilation of the cervixes. However, there were a few cases in which manual rotation was attempted before full dilation of the cervix, suggesting that the rate of malrotation was higher. The effect of prophylactic manual rotation at the early second stage of labor on decreasing operative delivery remains controversial.[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e][\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] These studies suggest that the best time for malrotation diagnosis and manual rotation enforcement is in the latter part of the second stage of labor. Evidence to choose CSEA or DPE and the establishment of a method and timing for manual rotation are needed.\u003c/p\u003e\u003cp\u003eThis study highlights the importance of education on delivery assistance. Our facility uses videos of Kielland forceps delivery to educate novice obstetricians,[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] which is one of our greatest strengths in handling the highest numbers of deliveries with labor analgesia in our country.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] In the era of the increasing use of labor analgesia in our country, obtaining the skill of Kielland forceps use would be an essential option. Training for a safe operative birth is a key priority in obstetrics.[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] As in the Royal College of Obstetricians and Gynecologists Operative Birth Simulation Training (ROBuST) course in the UK, the Kielland forceps technique is being handed down using the training program.[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] As a result of this education, Kielland forceps delivery is widely used across the whole country.\u003c/p\u003e\u003ch2\u003e5. Strength and Limitations\u003c/h2\u003e\u003cp\u003eThe greatest strength of our study is that it is the first to determine the association between malrotation and the use of labor analgesia using PSM. This matching was conducted to assess the effect of labor analgesia on malrotation, excluding other risks that might affect malrotation. Additionally, this study was conducted at a single center, which means that the management of delivery was homogeneous.\u003c/p\u003e\u003cp\u003eThis study had some limitations. First, as in all observational studies, confounders could be a concern, despite the statistical effort made. Therefore, the clinical implications of our study should be interpreted with caution, as we may need to measure unknown factors associated with malrotation. Second, this observational study was conducted at our single institution. The analgesic effect of epidural anesthesia with spinal anesthesia is more significant compared with epidural anesthesia alone. Applying our results to all parturient might introduce some bias.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe conclude that labor analgesia is associated with an increased rate of malrotation and instrumental delivery. However, labor analgesia does not seem to affect the rate of vaginal delivery, with a high attempt and success rate of manual rotation and the option of Kielland forceps delivery.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ePSM: Propensity Score Matching\u003c/p\u003e\n\u003cp\u003eCSEA: Combined Spinal-Epidural Anesthesia\u003c/p\u003e\n\u003cp\u003eDPE: Dural Puncture Epidural\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective cohort study was approved by the Ethics Committee of Juntendo University Hospital (E23-0351) in accordance with the Declaration of Helsinki. Due to the nature of the study, the need for informed consent to the individual was waived.\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\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eThe data that support the findings of this study are available from the corresponding author\u003c/strong\u003es \u003cstrong\u003eupon reasonable request.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare no conflict of interest with regards to this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funds, grants, or other support was received\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNT contributed to the acquisition and analysis of the data, interpretation of the results, and drafted the original manuscript. JT contributed to the study conceptualization and interpretation of the results. JT and AI critically revised the manuscript and supervised the conduct of the study. SU and SN contributed to the analysis of the data and interpretation of the result and critically revised the manuscript. All authors reviewed the draft manuscript and approved the final version of manuscript to be published.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Editage (https://www.editage.jp) for editing this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eFitzpatrick M, McQuillan K, O\u0026apos;Herlihy C. Influence of persistent occiput posterior position on delivery outcome. Obstet Gynecol. 2001;98(6):1027-1031. doi:10.1016/s0029-7844(01)01600-3 \u003c/li\u003e\n\u003cli\u003eSizer AR, Nirmal DM. Occiput posterior position: associated factors and obstetric outcome in nulliparas. 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Manual rotation to reduce caesarean delivery in persistent occiput posterior or transverse position. \u003cem\u003eJ Matern Fetal Neonatal Med\u003c/em\u003e. 2011;24(1):65-72. doi:10.3109/14767051003710276\u003c/li\u003e\n\u003cli\u003eAndo H, Makino S, Takeda J, et al. Comparison of the labor curves with and without combined spinal-epidural analgesia in nulliparous women- a retrospective study. \u003cem\u003eBMC Pregnancy Childbirth\u003c/em\u003e. 2020;20(1):467. doi:10.1186/s12884-020-03161-x.\u003c/li\u003e\n\u003cli\u003eBertholdt C, Piffer A, Pol H, Morel O, Guerby P. Management of persistent occiput posterior position: the added value of manual rotation. \u003cem\u003eInt J Gynaecol Obstet\u003c/em\u003e. 2022;157(3):613-617. doi:10.1002/ijgo.13874\u003c/li\u003e\n\u003cli\u003eDeLancey JOL, Masteling M, Pipitone F, LaCross J, Mastrovito S, Ashton-Miller JA.Pelvic floor injury during vaginal birth is life-altering and preventable: what can we do about it? \u003cem\u003eAm J Obstet \u003c/em\u003e\u003cem\u003eGynecol\u003c/em\u003e. 2024 March;230(3):279-294.e2. doi:10.1016/j.ajog.2023.11.1253\u003c/li\u003e\n\u003cli\u003eTakeda S, Takeda J, Koshiishi T, Makino S, Kinoshita K. Fetal station based on the trapezoidal plane and assessment of head descent during instrumental delivery. \u003cem\u003eHypertens Res Pregnancy\u003c/em\u003e. 2014;2(2):65-71. doi:10.14390/jsshp.2.65\u003c/li\u003e\n\u003cli\u003eMatsubara S, Lefor AK. 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Kielland\u0026apos;s rotational forceps delivery: A comparison of maternal and neonatal outcomes with rotational ventouse or second stage caesarean section deliveries. \u003cem\u003eEur J Obstet Gynecol Reprod \u003c/em\u003e\u003cem\u003eBiol\u003c/em\u003e. 2020;254:175-180. doi:10.1016/j.ejogrb.2020.08.026\u003c/li\u003e\n\u003cli\u003eO\u0026rsquo;Brien S, Day F, Lenguerrand E, Cornthwaite K, Edwards S, Siassakos D. Rotational forceps versus manual rotation and direct forceps: A retrospective cohort study. \u003cem\u003eEur J Obstet Gynecol Reprod \u003c/em\u003e\u003cem\u003eBiol\u003c/em\u003e. 2017;212:119-125. doi:10.1016/j.ejogrb.2017.03.031\u003c/li\u003e\n\u003cli\u003eChau A, Bibbo C, Huang C-C, et al. Dural puncture epidural technique improves labor analgesia quality with fewer side effects compared with epidural and combined spinal epidural techniques: A randomized clinical trial. \u003cem\u003eAnesth \u003c/em\u003e\u003cem\u003eAnalg\u003c/em\u003e. 2017;124(2):560-569. doi:10.1213/ANE.0000000000001798\u003c/li\u003e\n\u003cli\u003eBlanc J, Castel P, Mauviel F, et al. Prophylactic manual rotation of occiput posterior and transverse positions to decrease operative delivery: the PROPOP randomized clinical trial. \u003cem\u003eAm J \u003c/em\u003e\u003cem\u003eObstet\u003c/em\u003e\u003cem\u003e \u003c/em\u003e\u003cem\u003eGynecol\u003c/em\u003e. 2021;225(4):444.e1-444.e8. doi:10.1016/j.ajog.2021.05.020\u003c/li\u003e\n\u003cli\u003eVerhaeghe C, Corroenne R, Spiers A, et al. Delivery mode after manual rotation of occiput posterior fetal positions: A randomized controlled trial. \u003cem\u003eObstet \u003c/em\u003e\u003cem\u003eGynecol\u003c/em\u003e. 2021;137(6):999-1006. doi:10.1097/AOG.0000000000004386\u003c/li\u003e\n\u003cli\u003eTakeda J, Makino S, Itakura A, Takeda S. Technique of rotational forceps delivery using UTokyo Kielland Forceps. \u003cem\u003eHypertens\u003c/em\u003e\u003cem\u003e \u003c/em\u003e\u003cem\u003eRes Pregnancy\u003c/em\u003e. 2017;5(1):26-27. doi:10.14390/jsshp.HRP2017-005\u003c/li\u003e\n\u003cli\u003eTakeda S. \u003cem\u003eNew \u003c/em\u003e\u003cem\u003eAssessment\u003c/em\u003e\u003cem\u003e of \u003c/em\u003e\u003cem\u003eFetal\u003c/em\u003e\u003cem\u003e \u003c/em\u003e\u003cem\u003eDescent\u003c/em\u003e\u003cem\u003e and \u003c/em\u003e\u003cem\u003eForceps\u003c/em\u003e\u003cem\u003e \u003c/em\u003e\u003cem\u003eDelivery\u003c/em\u003e. Springer; 2018.\u003c/li\u003e\n\u003cli\u003eThe health academy; 2024, February 6. https://healthacademy.lancsteachinghospitals.nhs.uk/courses/surgical-simulation-training/robust-rcog-franchised/\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\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":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Fetal head malrotation, Kielland forceps delivery, Labor analgesia, Manual rotation, Propensity score matching","lastPublishedDoi":"10.21203/rs.3.rs-5353654/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5353654/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eFetal head malrotation is associated with prolonged labor, instrumental delivery, and perinatal complications. Previous studies have suggested an association between malrotation and labor analgesia, but this remains controversial. This study aimed to clarify whether malrotation increases with the use of labor analgesia.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis retrospective cohort study using propensity score matching. Medical records from January 2020 to January 2023 were reviewed. The study subjects were full-term pregnant women with singleton cephalic fetuses whose cervixes were fully dilated. The group without labor analgesia (Group C) was matched with the labor analgesia group (Group A) by propensity score matching. The primary outcome was the occurrence of malrotation. Secondary outcomes included rates of normal vaginal delivery, instrumental delivery, cesarean section, and success rate of attempted manual rotation. Pearson\u0026rsquo;s chi-square test was used to assess the association between the use of labor analgesia and outcomes.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eDuring the study period, 3868 women were included, 1164 cases were excluded due to the exclusion criteria, and 971 cases were further excluded due to missing data. Of 1735 eligible women, 88.4% received labor analgesia. After propensity score matching, 804 women were included, of whom 75% received labor analgesia (Group A) and 25% did not (Group C). The rate of malrotation was significantly higher in Group A compared to that in Group C (11.6% vs. 6.5%, p\u0026thinsp;=\u0026thinsp;0.03). The rate of instrumental delivery was significantly higher in Group A (25.7% vs. 14.9%, p\u0026thinsp;=\u0026thinsp;0.001). The distribution of the instrumental deliveries in Group A was as follows: Naegele forceps delivery was used in 87.1% of the cases, Kielland forceps in 5.2%, and vacuum extraction in 7.7%. There was no significant difference in the rate of vaginal delivery. Manual rotation was attempted in 84.3% of malrotation cases in Group A with a 64.4% success rate, with no significant difference of the success rate between the two groups.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eLabor analgesia is associated with an increased rate of malrotation and instrumental delivery. However, it does not seem to decrease the rate of vaginal delivery, given the high attempt and success rates of manual rotation and the availability of Kielland forceps delivery.\u003c/p\u003e","manuscriptTitle":"The association between fetal head malrotation and labor analgesia: a propensity score-matched analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-20 11:20:37","doi":"10.21203/rs.3.rs-5353654/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-16T08:29:57+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-04T17:54:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"106196151179871814312251953562381955945","date":"2024-12-26T16:55:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-10T12:06:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"73049792867531651724376885273192656624","date":"2024-12-03T09:39:17+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-12-02T02:36:17+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-10-31T07:10:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-10-30T09:09:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-10-30T09:09:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pregnancy and Childbirth","date":"2024-10-29T10:46:36+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"73fe3a83-c3a3-4595-bbfb-d9150b41675c","owner":[],"postedDate":"November 20th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-05T16:00:29+00:00","versionOfRecord":{"articleIdentity":"rs-5353654","link":"https://doi.org/10.1186/s12884-025-08431-0","journal":{"identity":"bmc-pregnancy-and-childbirth","isVorOnly":false,"title":"BMC Pregnancy and Childbirth"},"publishedOn":"2025-12-29 15:57:48","publishedOnDateReadable":"December 29th, 2025"},"versionCreatedAt":"2024-11-20 11:20:37","video":"","vorDoi":"10.1186/s12884-025-08431-0","vorDoiUrl":"https://doi.org/10.1186/s12884-025-08431-0","workflowStages":[]},"version":"v1","identity":"rs-5353654","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5353654","identity":"rs-5353654","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}