Clinical Question: How risky is a trial of labor after cesarean delivery for uterine rupture and other patient-oriented outcomes?

Setting: Various (meta-analysis)

Study Design: Meta-analysis (other)

Synopsis: In this skillfully performed evidence review that was conducted for the Agency for Healthcare Research and Quality, investigators evaluated the risk of uterine rupture, and maternal and perinatal consequences of uterine rupture, in women who choose trial of labor or elective repeat cesarean section after a previous cesarean delivery. Included were 21 cohort and case-control studies of at least fair quality. No randomized controlled trials were available. Studies based on International Classification of Diseases, 9th rev. codes in administrative data sets were specifically excluded because of the poor diagnostic accuracy of such data. The incidence of symptomatic uterine rupture was 3.8 per 1,000 patients in the trial of labor groups and 1.1 per 1,000 in the elective repeat cesarean section groups, or an additional 2.7 ruptures per 1,000 patients (95 percent confidence interval [CI], 0.73 to 4.73; number needed to treat to harm [NNTH] = 370).

Overall, six perinatal deaths were reported in 74 symptomatic ruptures, or 1.4 perinatal deaths per 10,000 trials of labor (95 percent CI, zero to 9.8; NNTH = 7,143). There were seven hysterectomies in 60 women with symptomatic rupture among women who chose trial of labor, or 3.4 hysterectomies per 10,000 trials of labor (95 percent CI, zero to 12.6; NNTH = 2,941), and no significant difference in hysterectomy rates overall. No maternal deaths were reported, and there was no difference in the incidence of asymptomatic uterine rupture. Oxytocin was associated with a two- to fourfold increase in the risk of uterine rupture in two case-control studies, but the use of oxytocin or prostaglandin was not associated with increased risk of uterine rupture in prospective cohort studies.

Bottom Line: Based on the best research, as compared with trial of labor, approximately 370 elective repeat cesarean sections would have to be performed to avoid one symptomatic uterine rupture. More than 7,000 elective repeat cesarean sections would be needed to prevent one perinatal death associated with uterine rupture, and almost 3,000 elective repeat cesearean sections would be needed to prevent one hysterectomy. No maternal deaths occurred among women who chose trial of labor or elective repeat cesarean section in the studies included in this review. There is insufficient evidence to judge whether induction of labor with oxytocin or prostaglandins increases the risk of symptomatic uterine rupture. This information should be included in the consent process for women who must choose between trial of labor and elective repeat cesarean section. (Level of Evidence: 2a)