A randomized controlled trial of 24-hour vaginal dinoprostone pessary compared to gel for induction of labor in term pregnancies with a Bishop score ≤ 4

Objective. To compare 24-hour controlled-release vaginal dinoprostone pessary vs. gel for induction of labor at term in women with an unfavorable cervix. Design. Randomized controlled trial. Setting. University hospital. Population. A total of 133 women with singleton pregnancies, fetal cephalic presentation, Bishop score < 4, gestational age of 37-42 weeks, no previous cesarean section and intact membranes admitted for induction of labor. Methods. Random allocation to either 24-hour 10-mg controlled-release vaginal dinoprostone pessary or repeat doses of 2 mg vaginal dinoprostone gel. Main outcome measures. Rate of spontaneous vaginal, operative vaginal and cesarean delivery. Results. The rate of spontaneous vaginal delivery was significantly higher in the pessary group (72%) than in the gel group (54%), paralleled by a lower rate of operative vaginal deliveries (3 vs. 15%). The difference in cesarean section rate (25 vs. 31%) did not reach statistical significance. Both methods of induction of labor appeared to be safe, with no cases of 5-minute Apgar scores < 7 or episodes of uterine hyperstimulation in either group. The medication cost was lower in the pessary group, with a median saving of 50.20euro compared to the gel group. Conclusions. Both the 24-hour dinoprostone vaginal pessary and the vaginal gel appear to be safe for labor induction. In women induced at term with a Bishop score < 4 the pessary achieved a significantly higher rate of spontaneous vaginal delivery.