Outcome after elective labor induction in nulliparous women: a matched cohort study

OBJECTIVE: To determine whether elective induction of labor in nulliparous women is associated with changes in fetomaternal outcome when compared with labor of spontaneous onset.Study Design: All 80 labor wards in Flanders (Northern Belgium) comprised a matched cohort study. From 1996 through 1997, 7683 women with elective induced labor and 7683 women with spontaneous labor were selected according to the following criteria: nulliparity, singleton pregnancy, cephalic presentation, gestational age at the time of delivery of 266 to 287 days, and birth weight between 3000 and 4000 g. Each woman with induced labor and the corresponding woman with spontaneous labor came from the same labor ward, and they had babies of the same sex. Both groups were compared with respect to the incidence of cesarean delivery or instrument delivery and the incidence of transfer to the neonatal ward. RESULTS: Cesarean delivery (9.9% vs 6.5%), instrumental delivery (31.6% vs 29.1%), epidural analgesia (80% vs 58%), and transfer of the baby to the neonatal ward (10.7% vs 9.4%) were significantly more common (P <.01) when labor was induced electively. The difference in cesarean delivery was due to significantly more first-stage dystocia in the induced group. The difference in neonatal admission could be attributed to a higher admission rate for maternal convenience when the women had a cesarean delivery. CONCLUSION: When compared with labor of spontaneous onset, elective labor induction in nulliparous women is associated with significantly more operative deliveries. Nulliparous women should be informed about this before they submit to elective induction.