Outcomes of Elective Induction of Labor versus Expectant Management among Obese Women at ≥39 Weeks.

Abstract

Maternal obesity is associated with many adverse obstetric outcomes including cesarean delivery. It is unclear whether induction of labor can reduce these risks. Previous studies report conflicting results on the outcomes of elective induction of labor among obese women. This study aimed to compare maternal and neonatal outcomes between obese women undergoing elective induction of labor and those undergoing expectant management at ≥39 weeks. This was a retrospective cohort study from the Consortium on Safe Labor of obese women (defined by prepregnancy body mass index≥ 30kg/m2) with singleton gestations at ≥39 weeks without medical comorbidities from 2002 through 2008. Women scheduled for medically indicated induction of labor were excluded. The primary outcome of cesarean delivery was compared between obese women undergoing elective induction of labor and expectant management during 39th, 40th, and 41st weeks using univariable and multivariable analyses, stratifying by parity. In all, 7,298 nulliparous and 9,789 parous women were eligible for analysis. After controlling for potential confounders, elective induction of labor during 39th week in nulliparous and parous women was associated with lower odds of cesarean delivery (39.1 vs. 41.6%, adjusted odds ratio [OR]: 0.47, 95% confidence interval [CI]: 0.30-0.74 for nulliparous and 5.5 vs. 10.1%, adjusted OR: 0.34, 95% CI: 0.20-0.61 for parous women) compared with expectant management. Elective induction of labor during 40th and 41st weeks was not associated with lower odds of cesarean delivery. In addition, macrosomia was reduced in nulliparous women undergoing elective induction of labor during the 40th week (12.1 vs. 18.5%, adjusted OR: 0.56, 95% CI: 0.35-0.87) and in parous women undergoing elective induction of labor during 39th (11.6 vs. 17.6%, adjusted OR: 0.50, 95% CI: 0.38-0.66) and 40th weeks (16.4 vs. 22.2%, adjusted OR: 0.53, 95% CI: 0.36-0.78). Elective induction of labor at 39 weeks, when compared with expectant management, was associated with lower cesarean deliveries in obese nulliparous and parous women.