A randomized comparison of prostaglandin E2, oxytocin, and the double-balloon device in inducing labor

To compare the efficacy of three methods for ripening and dilating the unfavorable cervix for induction of labor.

Pregnant women having an indication for induction of labor with a singleton vertex fetus, intact membranes, and Bishop score of no more than 4 were randomized to one of three induction methods: intravaginal prostaglandin (PG) E2 tablets (3 mg) followed by a second dose if labor did not start; continuous intravenous oxytocin drip; or the Atad Ripener Device, with inflation of both balloons and removal after 12 hours. For all patients, the cervix was assessed by the same investigator before induction and 12 hours later.

Thirty subjects were included in the PGE2 group, 30 in the oxytocin group, and 35 in the Atad Ripener Device group. The postpartum course was comparable in all. The change in Bishop score in the PGE2 and Atad Ripener Device groups was significantly better than in the oxytocin group (median and range of 5[0-9] and 5[0-7], respectively, versus 2.5 [0-9]; P < .01). Cervical dilation more than 3 cm was more frequent in the Atad Ripener Device group compared with both the PGE2 and oxytocin groups (85.7 versus 50 and 23.3%, respectively; P < .01). The trial of induction failed in only two patients (5.7%) in the Atad Ripener Device group, compared with six (20%) in the PGE2 and 16 (53.3%) in the oxytocin groups (P < .001). Mean (+/- standard deviation) induction-to-delivery interval was 21.3 +/- 7.0 hours in the Atad Ripener Device group, 23.2 +/- 12.5 hours in the PGE2 group, and 28.2 +/- 14.7 hours in the oxytocin group. The success rate for vaginal delivery was significantly better in the Atad Ripener Device and PGE2 groups compared with the oxytocin group (77.1 and 70%, respectively, versus 26.7%; P < .01).

The Atad Ripener Device had a significantly better success rate for cervical dilation and a lower failure rate than those for PGE2 and oxytocin. The PGE2 and Atad Ripener Device groups had better results than the oxytocin group in regard to Bishop score change and induction-to-delivery interval. The Atad Ripener Device may be a superior method for cervical ripening and labor induction in patients with unfavorable cervices.