Transactions of the Twentieth Annual Meeting of the Society for Maternal-Fetal Medicine
Elective repeat cesarean delivery versus trial of labor: A meta-analysis of the literature from 1989 to 1999

Presented at the Twentieth Annual Meeting of the Society for Maternal-Fetal Medicine, Miami Beach, Florida, January 31–February 5, 2000.
https://doi.org/10.1067/mob.2000.108890Get rights and content

Abstract

Objective: The aim of this study was to compare a trial of labor with elective repeat cesarean delivery among women with previous cesarean delivery. Study Design: We searched MEDLINE and EMBASE databases from 1989 through 1999 with the following terms: vaginal birth after cesarean delivery, trial of labor, trial of scar, and uterine rupture. We included all controlled trials from developed countries in which the control group had been eligible for a trial of labor. Outcomes of interest were uterine rupture, hysterectomy, maternal febrile morbidity, maternal mortality, 5-minute Apgar score <7, and fetal or neonatal mortality. We computed pooled odds ratios for each outcome. Results: The search strategy identified 52 controlled studies, 37 of which were excluded because many of the control subjects were not eligible for a trial of labor. Fifteen studies with a total of 47,682 women were included. Uterine rupture occurred more frequently among women undergoing a trial of labor than among those undergoing elective repeat cesarean delivery (odds ratio, 2.10; 95% confidence interval, 1.45-3.05). There was no difference in maternal mortality risk between the 2 groups (odds ratio, 1.52; 95% confidence interval, 0.36-6.38). Fetal or neonatal death (odds ratio, 1.71; 95% confidence interval, 1.28-2.28) and 5-minute Apgar scores <7 (odds ratio, 2.24; 95% confidence interval, 1.29-3.88) were more frequent in the trial of labor group than in the control group. Mothers undergoing a trial of labor were less likely to have febrile morbidity (odds ratio, 0.70; 95% confidence interval, 0.64-0.77) or to require transfusion (odds ratio, 0.57; 95% confidence interval, 0.42-0.76) or hysterectomy (odds ratio, 0.39; 95% confidence interval, 0.27-0.57). Conclusion: A trial of labor may result in small increases in the uterine rupture rate and in fetal and neonatal mortality rates with respect to elective repeat cesarean delivery. Maternal morbidity, including febrile morbidity, and the need for transfusion or hysterectomy may be reduced with a trial of labor. (Am J Obstet Gynecol 2000;183:1187-97.)

Section snippets

Material and methods

We identified relevant studies through a computer search of English-language abstracts in the MEDLINE and EMBASE databases for the years 1989 and 1999. We also searched the registry of clinical trials maintained by the Cochrane Pregnancy and Childbirth Group. A variety of searches were conducted with combinations of the following medical subject heading terms: vaginal birth after cesarean, trial of labor, trial of scar, and uterine rupture. We supplemented our search by cross-checking the

Results

All included studies provided information about probability of successful vaginal birth among women undergoing a trial of labor. Across the 15 studies a total of 28,813 women underwent a trial of labor, and 20,746 achieved successful vaginal birth (weighted average 72.3%; 95% confidence interval, 71.8%-72.8%).

Eleven studies that contained a total of 39,116 women*examined the risk of uterine rupture for a trial of labor compared with elective

Comment

Our analyses suggest that symptomatic uterine rupture, the most feared complication among women with previous cesarean delivery, may be about twice as common among women undertaking a trial of labor than among women undergoing elective repeat cesarean delivery. The absolute risk of this outcome remains low, however, and it is not nil even with a policy of elective repeat cesarean delivery. According to the odds ratios computed in our analysis, between 374 and 809 women would need to undergo

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