Early versus late amniotomy for labour induction: a randomized controlled trial.

Objective: To evaluate the impact of early vs. late amniotomy on delivery mode in women undergoing induction of labor.

Methods: 143 women admitted for induction were randomized to early amniotomy (EA, concomitant with the beginning of oxytocin infusion; n = 71) or to late amniotomy (LA, four hours after the beginning of oxytocin; n = 72). Randomization was stratified by parity. The primary outcome was the rate of cesarean. Secondary outcomes were duration of labor and intrapartum fever.

Results: The cesarean rate was similar between groups (18% vs. 17% among nulliparous; and 3% vs. 0% among parous women, in EA and LA group, respectively). However, EA was associated with shorter oxytocin-to-delivery interval (12 vs. 15 h) and a non-significant decrease in intrapartum fever (3% vs. 25%) than LA in nulliparous women (p = 0.05).

Conclusions: For women undergoing oxytocin induction, early amniotomy is associated with shorter labor in nulliparous women with no effect on the risk of cesarean section in both nulliparous and multiparous women.