Indexed on: 01 Mar '19Published on: 01 Mar '19Published in: American Journal of Obstetrics & Gynecology
Elective induction of labor at 39 weeks among low-risk nulliparous women has reduced the chance of cesarean and other adverse maternal and perinatal outcomes in a randomized trial, although its clinical effectiveness in non-research settings remains uncertain. To perform a systematic review of observational studies that compared elective induction of labor at 39 weeks among nulliparous women to expectant management, and to use meta-analytic techniques to estimate the association of elective induction with cesarean delivery, as well as other maternal and perinatal outcomes. Studies were eligible for this meta-analysis only if they: (1) were observational; (2) compared women undergoing labor induction at 39 weeks with women undergoing expectant management beyond that gestational age; (3) included women in the induction group only if they had no other indication for labor induction at 39 weeks; and (4) provided data specifically for nulliparous women. The pre-defined primary outcome was cesarean delivery, and secondary outcomes representing other maternal and perinatal morbidities also were evaluated. Outcome data from different studies were combined to estimate pooled relative risks (RR) with 95% confidence intervals using random-effects models. Of 375 studies identified by the initial search, 6 cohort studies, which included 66,019 women undergoing elective labor induction at 39 weeks and 584,390 undergoing expectant management, met inclusion criteria. Elective induction of labor at 39 weeks was associated with a significantly lower frequency of cesarean delivery (26.4% vs. 29.1%; RR 0.83 (95% CI 0.74-0.93)), as well as of peripartum infection (2.8% vs. 5.2%; RR 0.53 (95% CI 0.39-0.72)). Neonates of women in the induction group were less likely to have respiratory morbidity (0.7% vs. 1.5%; RR 0.71 (95% CI 0.59-0.85)); meconium aspiration syndrome (0.7% vs. 3.0%; RR 0.49 (95% CI 0.26-0.92)); and neonatal intensive care unit admission (3.5% vs. 5.5%; RR 0.80 (95% CI 0.72-0.88)). There also was a lower risk of perinatal mortality (0.04% vs. 0.2%; RR 0.27 (95% CI 0.09-0.76)). This meta-analysis of 6 cohort studies demonstrates that elective induction of labor at 39 weeks, compared to expectant management beyond that gestational age, was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, including respiratory morbidity, intensive care unit admission, and mortality. Copyright © 2019 Elsevier Inc. All rights reserved.