A Randomized Double-Blind Trial Comparing Vaginal Misoprostol Versus Prostaglandin E2 for Labour Induction at Term

Objectives: To determine the efficacy and safety of vaginal misoprostol (50mcg) compared to vaginal prostaglandin E2 (PGE2) for induction of labour. Design: A randomized double-blind clinical trial. Setting: Obstetric Unit, King Faisal Armed Forces Hospital, Southern Region, Khamis Mushayt, Kingdom of Saudi Arabia. Participants: Two hundred and twenty pregnant women at term requiring induction. Intervention: The women were randomized to receive vaginal misoprostol 50mcg or Prostaglandin E2 3mg. The dose was repeated 6, 24 and 30 hours after the first dose if an adequate uterine response was not achieved. Main outcome measures: The primary outcome was vaginal delivery within 24 hours. Secondary outcomes were the time from induction to delivery, the need for oxytocin augmentation, the mode of delivery, the frequency of side effects, and the maternal and neonatal outcomes. Results: There were no significant differences in maternal characteristics or indications for induction. The percentage of women who achieved vaginal delivery within 24 hours was higher in the misoprostol group compared with the PGE2 group (67% Vs. 53%, p 0.05) and fewer patients in this group needed more than 2 doses (11% Vs. 28%, p 0.05). The time to vaginal delivery was shorter in the misoprostol group when compared with the PGE2 group (15.2 hours Vs. 20.2 hours, p 0.05). Fewer patients in the misoprostol group required oxytocin augmentation (24% Vs. 50%, p 0.0001). There were no significant differences between the two groups with respect to rates of caesarean section, fetal heart rate anomalies, tachysystole, hyperstimulation, meconium passage and neonatal outcome. Conclusions: Induction of labour with vaginal misoprostol is more effective than vaginal PGE2 with no apparent adverse effect on the mother or the fetus.