Elective repeat cesarean delivery vs trial of labor: a comparison of morbidities in a community hospital setting

Abstract

Objective: In an attempt to reduce the cesarean delivery rate nationally, many obstetricians are offering a trial of labor to their patients who have had a prior low transverse cesarean delivery. Many studies have demonstrated the success and safety of a vaginal birth after cesarean. However, few studies have actually compared elective repeat cesareans with a trial of labor. Recent articles suggest that the morbidities associated with a failed trial of labor (TOL) may be more serious than that associated with an elective repeat cesarean delivery (RC/D). Our objective was to review and compare the morbidities and complications of repeat elective cesarean delivery versus patients attempting a trial of labor in our institution. Methods and Materials: A retrospective or nonconcurrent cohort study was conducted. Inclusion criteria included all women at our institution who had delivered from July 1993 through March 1997 and had a prior cesarean delivery. Patients were eligible for a trial of labor according to the recommendations of ACOG Practice Patterns. Exclusion criteria were nonvertex presentation, prior classical or T-incision, placenta previa, previous myomectomy, or multiple gestation. The patients were divided into those who underwent an elective repeat delivery and those who consented to a trial of labor. Outcomes studied included major complications (uterine rupture or operative injury) and minor complications (puerperal fever, postpartum hemorrhage requiring transfusion or operative intervention, or abdominal wound infection). Data were ascertained from medical records, the delivery log book, and the Quality Improvement data base. Prior to performing this study, a power analysis was conducted using an alpha of 0.05 and beta of 0.20. The required number in each arm was 2,280 to determine a 50% difference in outcome. Results: There were 1,148 women who had a repeat cesarean delivery during the study time period. Of that, 174 were excluded by the criteria, leaving 973 eligible. There were 1,030 women who underwent a trial of labor. Seven hundred seventy-three women successfully delivered vaginally (75%). The overall maternal morbidity was 2.4%; 0.8% had a major complication and 1.5% had a minor complication. The total complication rate was similar for both the trial of labor group (TOL) and the elective repeat cesarean delivery group (RC/D): 2.33% and 2.57%, respectively. However, major complications were more frequent among those that attempted a trial of labor than those who underwent an elective repeat cesarean delivery; 1.65% versus 0.1% (relative risk 16.08 with a 95% CI of 2.14–120.57; P = .00024). The relative risk for minor complications in the TOL group compared to the RC/D group was 0.28 with a 95% CI 0.12–0.64 ( P = .001). Stratified analysis of the TOL group was performed. Compared to the RC/D group, those who failed VBAC had a relative risk for major complications of 56.85 using a 95% CI of 7.45–428.37. The successful VBAC group did not have statistically higher major complication rate (RR = 2.52, CI 0.23–27.74, P = .4). Conclusions: At our institution, there is a trend that major maternal complications are more frequent among those who have a trial of labor compared to those who have an elective repeat cesarean delivery. This trend was even more evident in those who failed a VBAC trial. When VBAC was successful, complications did not seem to be higher than repeat cesarean delivery. Our study did not have the power because of insufficient numbers in each arm. However, data collection is continuing to achieve the power to this study. This prompted us to reconsider the safety for a trial of labor. Perhaps more stringent criteria for selection of VBAC candidates and determination of when a trial of labor should be abandoned need to be defined. Ongoing study is warranted in this area.