Impact of early versus late amniotomy on induction of labor in nulliparous women after vaginally administered misoprostol: A randomized clinical trial

Objective: To investigate the effect of early versus late amniotomy after induction of labor (IOL) with vaginally administered misoprostol. Methods: This randomized clinical trial was conducted at the Department of Obstetrics and Gynecology, Menoufia University, from May 2019 to March 2020, and included 120 nulliparous women at term (≥ 37 weeks' gestation) undergoing IOL. Computer-generated randomization was used to randomize the participants into either the early amniotomy group (3 cm cervical dilatation; n = 60) or the late amniotomy group (7 cm cervical dilatation; n = 60). All participants received misoprostol (25 μg) vaginally to induce labor. The primary outcome was the induction-to-delivery interval, defined as the time from the initiation of IOL to the time of delivery. Results: Women in the early amniotomy group had a shorter duration of labor (12.60 ± 5.36 h) than those in the late amniotomy group (16.67 ± 7.26 h). The mean time from rupture of the fetal membrane to delivery was significantly shorter in the late (2.51 ± 0.36 h) than in the early amniotomy group (3.1 ± 0.89 h). There was no statistically significant difference between the groups in terms of maternal complications (fever, nausea, vomiting, and uterine hyperstimulation) or neonatal complications (meconium-stained liquor, APGAR score <7 at 1 and 5 min, and neonatal intensive care unit admission). Conclusions: IOL using vaginally administered misoprostol followed by early amniotomy was accompanied by a shorter duration of labor and decreased use of oxytocin. There was no significant difference between the early and late amniotomy groups in terms of the rate of cesarean section or maternal and neonatal complications.