Objective: We compared the maternal and neonatal outcomes between elective labor induction versus spontaneous labor or rupture of membranes in women with non-complicated singleton pregnancies who tried labor after 39 weeks of gestation.
Methods: This was a retrospective cohort study of 342 women with singleton pregnancy who tried labor after 39 weeks of gestation in a single institution between 2018 and 2021. Pregnant women who delivered before 39 weeks of gestation, who delivered by elective cesarean section, or with multiple gestation or complicated pregnancy were excluded. Subjects were categorized into two groups: pregnant women who underwent elective labor induction (induction group) and pregnant women who had spontaneous labor or rupture of membranes (spontaneous group). Pregnancy outcomes and neonatal outcomes were reviewed. Subgroup analyses were done in nulliparous and multiparous women.
Results: Maternal characteristics were similar in the two groups. Cesarean section rate was significantly higher in the induction group than the spontaneous group (27.0% vs. 14.6%, P=0.005). However, the indications for cesarean delivery were significantly different between the two groups: induction failure (35.4% vs. 0%), failure to progress (64.6% vs. 79.2%), and fetal distress (0% vs. 20.8%) in the induction group and spontaneous group (P<0.001), respectively. Postoperative complications were comparable between the two groups, but postoperative hemoglobin drop more than 10% was significantly more common in the induction group. Neonatal outcomes were similar between the two groups. In nulliparous women, cesarean section rate was significantly higher in the induction group (37.0% vs. 20.2%, P=0.004).
Conclusion: Elective labor induction in non-complicated singleton women at 39 weeks of gestation was associated with a higher cesarean section rate than spontaneous labor or rupture of membranes. And this was mostly due to a higher rate of cesarean delivery for induction failure in nulliparous women.