Misoprostol is more efficacious for labor induction than prostaglandin E-2, but is it associated with more risk?

OBJECTIVE: Our purpose was to compare the efficacy and safety of misoprosto l with dinoprostone (Prepidil) for labor induction. STUDY DESIGN: in a randomized, controlled trial of labor induction, patient s were randomly assigned to receive either 50 mu g of intravaginal misopros tol every 4 hours or 0.5 mg of intracervical prostaglandin E-2 every 6 hour s. Eligibility criteria included gestation of greater than or equal to 31 w eeks, Bishop score <6, and fewer than 12 contractions per hour. Primary out comes were cesarean section, induction to delivery time, oxytocin use, and fetal distress requiring delivery. RESULTS: One hundred fifty-nine women were randomly assigned to receive mis oprostol (n = 81) or Prepidil (n = 78). There were no differences in the in dication for induction, preinduction Bishop score, epidural use, or cesarea n section rate. Mean time to delivery was significantly shorter in the miso prostol group (19 hours 50 minutes) than in the Prepidil group (28 hours 52 minutes) (P = .005). Only 58% of women in the misoprostol group required o xytocin augmentation, in comparison with 88% of women receiving Prepidil (P = .00002). However, 41% of women receiving misoprostol and 17% receiving P repidil had late decelerations or bradycardias (P = .001), and 20% of the m isoprostol group and 5% of the Prepidil group had deliveries for fetal dist ress (P = .05). CONCLUSIONS: Misoprostol is more efficacious than Prepidil for labor induct ion. However, the significantly increased incidence of abnormal fetal heart rate tracings and the trend in increased deliveries for fetal distress wit h misoprostol dosing of 50 mu g every 4 hours are of concern. These data su ggest that either a lower dose of misoprostol or less frequent dosing of mi soprostol should be considered.