Induction of labor versus expectant management among women with macrosomic neonates: a retrospective study

Background: The macrosomic fetus predisposes a variety of adverse maternal and perinatal outcomes. Although older studies have shown no benefit in inducing women of suspected macrosomic fetuses, more updated studies show different information.Objectives: The aim of our study was to compare induction of labor versus expectant management among women with macrosomic neonates weighing more than 4000 g at term (between 37°^/7 and 41^6/7 weeks' gestation).Study design: This was a retrospective cohort study of all live-born singleton pregnancies with macrosomic newborns who were delivered at our institution between 1 January 2000 and 1 June 2015. We compared the outcomes of induction of labor, at each gestational age (GA), between 37 and 41 weeks (study group) with ongoing pregnancy. The primary outcome was cesarean section (CS) rate. Secondary outcomes were composite maternal and neonatal outcome and birth injuries.Results: Overall, out of 3095 patients with macrosomic newborns who were included in the study, 795 women (25.7%) underwent induction of labor. The cesarean section rate was not found to be significantly different between the groups at all gestational ages, nor was the vaginal delivery rate. After adjusting for confounders, induction of labor at 40 and 41 weeks' gestation was associated with composite maternal outcome (adjusted odds ratio (aOR) 1.6, 95% confidence interval (CI): 1.3-2.1; aOR 1.7, 95% CI: 1.3-2.2, respectively) and composite neonatal outcome (aOR 1.6, 95% CI: 1.1-2.4; aOR 1.8, 95% CI: 1.1-2.9). Induction of labor at 40 weeks' gestation was also associated with increased risk of birth injuries (aOR 2.9, 95% CI: 1.4-6).Conclusions: Compared with ongoing pregnancy, induction of labor of women with macrosomic neonates between 37 and 41 weeks of gestation does not reduce the CS rate, nor does it increase the vaginal delivery rate. Moreover, induction of labor of those women beyond 39 weeks' gestation is associated with composite adverse maternal/neonatal outcome, specifically birth injuries.