Vaginal misoprostol for induction of labor: 25 vs. 50 microg dose regimen

To compare the efficacy and safety of two regimens of vaginal misoprostol for induction of labor.

In a randomized study, 185 women undergoing induction of labor were allocated to Group A (n=93), to be given 25 microg misoprostol and Group B (n=92), to be given 50 microg misoprostol. Intravaginal misoprostol was given every 4 h until the onset of labor. A maximum of six doses was administered.

Abnormal uterine contractions were more common in Group B compared to Group A: 33 (35.86%) vs. 10 (10.75%) cases, and significantly more women in Group B required tocolysis (9.78 vs. 3.23%). The induction-delivery interval (mean+/-S.D.) was 17.18+/-8.48 h in Group A and 9.37+/-5.87 h in Group B (P<0.05). Oxytocin infusion was used in 37.63% of women in Group A and 26.08% in Group B (P>0.05). The cesarean section rate was 17.20% in Group A and 14.13% in Group B (P>0.05). Cesarean for failed IOL was more common in Group A: 7 of 16 (43.8%) vs. 3 of 13 (23.1%) cesarean deliveries (P<0.05). Postpartum hemorrhage occurred in 9.78% of women in Group B compared to 2.15% in Group A (P<0.05). There was a trend for more neonatal complications in Group B, but this did not reach significance.

Although a dose of 50 microg of misoprostol results in a significantly shorter induction-delivery interval with less need for labor augmentation, there was an increased risk of uterine contractile abnormalities and postpartum hemorrhage. A regime using 25 microg of misoprostol every 4 h can induce labor safely and effectively.