Benefits and risks of induction of labor at 39 or more weeks in uncomplicated nulliparous women: a retrospective, observational study.

OBJECTIVE

To critically compare the benefits and risks of labor induction versus spontaneous labor in uncomplicated nulliparous women at 39 or more weeks of gestation.

METHODS

We conducted a retrospective, observational study of 237 nulliparous women who were at 39 or more weeks of a singleton pregnancy with vertex presentation and intact membranes. We compared maternal outcomes including the Cesarean section rate and neonatal outcomes in the induced labor and spontaneous labor groups.

RESULTS

Among the 237 women, 199 delivered vaginally (84.0%). The spontaneous labor group and induced labor group had a similar incidence of Cesarean delivery (17.7% vs. 12.3%, =0.300). The length of stay and blood loss during delivery were also similar between the groups (4.3±1.5 vs. 3.9±1.5 days and 1.9±1.3 vs. 1.8±1.0 mg/sL, respectively; all >0.05). Regarding neonatal outcomes, the rate of meconium-stained amniotic fluid, Apgar score <7 at 5 minutes, and intubation rate were similar between the groups (18.9% vs. 24.7%, 7.9% vs. 4.1%, and 6.1% vs. 4.4%, respectively, all >0.05). Only the neonatal intensive care unit admission rate was significantly lower in the induction group than in the spontaneous labor group (28.0% vs. 13.2%, =0.001).

CONCLUSION

Maternal adverse outcomes of labor induction at 39 weeks of gestation were similar to those in a spontaneous labor group in uncomplicated nulliparous women. Neonatal adverse events were also similar between the groups. It may be acceptable to schedule labor induction as long as 7 days before the estimated date, even when the indication is only relative.