Induction of Labor in Nulliparous Women With an Unfavorable Cervix: A Randomized Controlled Trial Comparing Double and Single Balloon Catheters and PGE2 Gel

There is no consensus on the optimal technique to achieve cervical ripening in nulliparous women before attempting labor induction. Common cervical ripening methods include a synthetic prostaglandin (PGE2) gel, a single balloon (Foley) catheter, or a double balloon catheter. Studies investigating these techniques have been limited by differences in patient population, design deficiencies, and inconclusive results. This randomized controlled trial compared these 3 induction methods for efficacy, safety, and the level of patient satisfaction in 330 term nulliparous women with unfavorable cervices. The study subjects were randomized to receive either a double balloon catheter (n = 107), single balloon (Foley) catheter (n = 110), or a PGE2 gel (n = 113). No difference was found in rates of cesarean delivery between the groups (double balloon 43%, single balloon 36%, and PGE2 37%, P = 0.567). The time from induction to delivery was longer in the double balloon group (median: 24.5 hours, 95% confidence interval: 23.7-30.6 hours) compared to single balloon (23.2, 20.8-25.8 hours) or PGE2 (23.8, 21.7-26.8 hours, P = 0.043). Use of the PGE2 gel for cervical ripening was associated with uterine hyperstimulation (14%), with none occurring in the other 2 groups. No adverse reactions occurred in the group receiving the single balloon catheter. Significantly more adverse reactions were noted in the PGE2 group (17 events) than in the double balloon catheter group (5 events; P < 0.001). The PGE2 group also had a lower median arterial pH: 7.25 (range: 6.91-7.41) in the PGE2 group, 7.26 (range: 7.03-7.40) in the double balloon group, and 7.26 (7.05-7.44) in the single balloon group (P = 0.050). Significantly less pain was reported by the women in the single balloon group during the cervical ripening phase: 36% had a pain score ≥4 in the single balloon group compared with 55% in the double balloon group and 63% in the PGE2 group (P < 0.001). The median overall satisfaction scores were the same in all 3 groups (8/10). These findings show that term women with unfavorable cervices have high cesarean delivery rates that are not affected by the method of induction. Although the efficacy of the induction techniques is similar, the data suggest to the investigators that a single balloon catheter is the safest and most acceptable method of cervical ripening.