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Cesarean Risk After Successful External Cephalic Version: a Matched, Retrospective Analysis

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Cesarean Risk After Successful External Cephalic Version: a Matched, Retrospective Analysis Journal of Perinatology (2009) 29, 96–100 r 2009 Nature Publishing Group All rights reserved. 0743-8346/09 $32 www.nature.com/jp ORIGINAL ARTICLE Cesarean risk after successful external cephalic version: a matched, retrospective analysis C Clock1, J Kurtzman2,3, J White3 and JH Chung3 1Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR, USA; 2Department of Obstetrics and Gynecology, Saddleback Memorial Medical Center, Laguna Hills, CA, USA and 3Department of Obstetrics and Gynecology, Irvine Medical Center, University of California, Orange, CA, USA has been associated with a higher neonatal morbidity than elective Objective: To determine the odds of cesarean, operative vaginal delivery cesarean delivery. 1,2 In an attempt to minimize the risks associated and vaginal birth after cesarean after successful external cephalic version with either breech vaginal delivery or elective cesarean delivery, the (ECV) compared with singleton pregnancies eligible for a trial of labor. American College of Obstetricians and Gynecologists recommended Study Design: A matched case–control study was performed using the application of external cephalic version (ECV) to reduce breech 3 Memorial Care OBStat Database from 1 January 1998 to 31 July 2006. We presentations in singleton gestations. ECV is a safe and effective identified 197 participants who underwent a successful ECV (study group) method that consists of rotating the fetus from breech to cephalic and compared them with the next two women presenting for labor presentation by external manipulation of the mother’s abdomen, 2,4 management, matched for parity, gestational age, delivery history with the success rate ranging from 44 to 77%. (previous cesarean delivery) and type of labor (spontaneous or induced). Although the intent of ECV is to decrease the overall cesarean delivery rate for breech presentation, there is controversy as to Result: There was no significant difference in the adjusted matched odds whether this is ultimately achieved. Some studies have shown an of cesarean delivery between the study group and control group overall increased rate of cesarean delivery following successful ECV, (16.8 vs 11.9%; odds ratio (OR) 1.70; 95% confidence interval (CI) 0.98 to whereas others have not.5–12 Part of the difficulty in drawing a 2.97), even when subanalyzed according to parity. There was also no conclusion from these studies is that differing control groups and significant difference in adjusted matched odds of operative vaginal matching characteristics have been used. In addition, small sample delivery for the study group and control group, 15.9 vs 8.9% (OR 1.06; sizes may have been a limiting factor in some studies. Further, 95% CI 0.32 to 3.51). Among patients with a prior cesarean, those who many have excluded participants with prior cesarean delivery, underwent successful ECV had a cesarean delivery rate of 11.1% compared making information on this subset of individuals limited. with 16.7% in the matched control group (OR 0.59; 95% CI 0.47 to 7.43). Therefore, the goals of this investigation were to settle the questions Conclusion: Cesarean delivery and operative vaginal delivery rates as to whether successful ECV truly lowers the rate of cesarean following successful ECV are not increased in our data set compared with delivery in patients with non-cephalic presentation and whether matched controls, even in patients with a prior cesarean delivery. This women undergoing successful ECV have a higher rate of cesarean information may be useful when counseling patients who are delivery as compared with those presenting for labor management contemplating an ECV attempt due to non-cephalic presentation at term. at term with spontaneous cephalic presentations. Journal of Perinatology (2009) 29, 96–100; doi:10.1038/jp.2008.227; published online 8 January 2009 Keywords: external cephalic version; cesarean delivery; breech presentation Methods This is a matched case–control study that was performed at Introduction Saddleback Memorial Medical Center, an academically affiliated, community-based hospital. Before study initiation, institutional Breech presentation complicates 3 to 4% of term pregnancies, and review board approval for human participant research was obtained planned vaginal delivery for a singleton, term, breech presentation from the Memorial Services Office of Research Administration. Correspondence: Dr C Clock, Division of Maternal-Fetal Medicine, Department of Obstetrics Cases were identified in a retrospective fashion using a and Gynecology, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Mail contemporaneously collected, quality assurance perinatal database Code L548, Portland, OR 97239, USA. known as OBStat. Cases were defined as participants with a E-mail: [email protected] Received 1 June 2008; revised 21 November 2008; accepted 23 November 2008; published online singleton gestation who underwent a successful ECV for 8 January 2009 malpresentation during the study period from 1 January 1998 to 31 Cesarean risk after successful cephalic version C Clock et al 97 July 2006. The obstetric and perinatal information of this study confidence interval (CI) for the primary outcome of cesarean population was retrieved from the Memorial Care OBStat Database. delivery were then calculated using conditional logistic regression. The information in this database is entered by a trained clinical Covariates in the multivariate model included diabetes mellitus, nurse and is checked weekly for accuracy. pre-eclampsia, cardiac disease and gestational age at delivery. All During the study period, the clinical protocol of the department analyses were performed using Stata, version 9.0 (StataCorp LP, was to offer ECV to women with a breech presentation at 36 weeks’ College Station, TX, USA). gestation or beyond. ECV was not offered or performed if the patient had any of the following contraindications: multifetal pregnancy, placenta previa, third trimester bleeding, oligohydramnios (amniotic fluid index <5), premature rupture of membranes, Results intrauterine growth restriction, previous uterine surgery other than During the study period, 914 participants presented with breech prior low-transverse cesarean section, gross fetal anomalies, non- presentation at >36 weeks’ gestation. ECV was attempted on 420 reassuring fetal heart tracing or uterine anomaly. Breech vaginal (46.0%) participants, of which 197 were successful (47.5%). We delivery for the term, singleton gestation was not routinely offered identified 394 matched controls for a total sample of 591 at our hospital during the study period. participants. Though delivery volume remained relatively steady in All ECV procedures in our hospital are performed by the our medical center during the study period (approximately 250 per Maternal–Fetal Medicine faculty members in a similar fashion. A month), the average number of ECV attempts during the study standard ECV order set was used by all practitioners. Before the period peaked at 3 per month in 2002 and had been decreasing procedure, the following clinical parameters are routinely since that time till it reached less than 1 per month. documented: confirmation by ultrasound that the fetus remains in There were no significant differences between the two groups a non-vertex presentation, adequacy of the amniotic fluid index, with respect to maternal age or medical complications including the absence of active labor and the presence of a reassuring fetal insulin-dependent diabetes, cardiac disease, gestational diabetes heart rate pattern by external fetal monitoring. Informed consent mellitus, chronic hypertension or pre-eclampsia (Table 1). Other for the procedure is then obtained. Following the establishment of demographic factors that may potentially impact the cesarean intravenous access, terbutaline 0.25 mg is administered delivery rate, such as ethnicity and epidural use, were not subcutaneously to all women immediately before the procedure. statistically significantly different between the groups. In contrast, Epidural anesthesia is not used. The external cephalic procedure is participants who underwent successful ECV had a higher then performed by a single physician with the assistance of a proportion of deliveries at 41 weeks’ gestation or later, though not nurse. The assistant monitors fetal presentation and heart rate by significant. ultrasound during the procedure. Before discharge, post-procedure Among those participants requiring induction of labor, the fetal monitoring is performed for a minimum of 1 h. The care of mean interval from ECV to induction was 13.6 days (range 0 to 38 women after ECV was the same as in those pregnancies with days). As induction status was one of the matching criteria, there spontaneous cephalic presentation. was no difference between the two groups (Table 1). Twenty Before study initiation, an a priori, two-sided, sample size patients (10.2%) underwent induction of labor within 24 h calculation was performed for our primary outcome of cesarean following successful ECV. Within this group, indications for delivery, utilizing prior studies in this area to estimate incidence induction included elective (15%), abnormal post-procedure non- rates.4–10,13 With an a error of 0.05, we determined that 197 stress tests (10%), post-dates (10%), suspected macrosomia (5%) patients and 394 controls, matched in a 2:1 fashion, would yield and pre-eclampsia (5%). The remaining indications for induction 80% power to detect a 10%
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