Randomized comparison of misoprostol and dinoprostone for preinduction cervical ripening and labor induction

Abstract

This study attempts to evaluate the clinical effects of prostaglandin (PG) E analogues in preinduction cervical ripening and labor induction and to compare the perinatal outcomes of these medications. Sixty women with term singleton pregnancies were randomized to receive dinoprostone vaginal tablets (group I) or misoprostol vaginal tablets (group II). The Bishop scores were evaluated before drug insertion and every 4 hours during induction. Clinical data and perinatal outcomes were also recorded. There were no significant differences in the preinduction conditions on mean initial Bishop scores between these two groups. Twelve hours after drug insertion, the mean Bishop scores were significantly better in group II (9.7 +/- 3.1 vs 7.3 +/- 2.5, p < 0.05). The mean time from insertion to delivery was shorter in group II (16.5 +/- 2.7 h vs 25.7 +/- 3.8 h, p < 0.001). There were no significant differences in spontaneous labor rate, need for oxytocin augmentation, type of delivery, and Doppler flow velocity waveforms of the umbilical artery. The average number of doses given per patient was 1.8 +/- 1.4 in group II vs 2.7 +/- 0.3 in group I (p < 0.05). The perinatal outcome was similar in the two groups. In conclusion, misoprostol not only appears to be a safe and effective agent for cervical ripening and labor induction but is also more efficient than dinoprostone.

PIP: The effectiveness of two prostaglandin E analogues in preinduction cervical ripening and labor induction was assessed in a randomized comparative study involving 60 nulliparous Taiwanese women with term singleton pregnancies. 30 women received 3 mg of dinoprostone vaginal tablets (group I); the remaining 30 were given 200 mcg of misoprostol vaginal tablets (group II). During induction, Bishop scores were evaluated every 4 hours. After 12 hours of induction, the mean Bishop score was 9.7 in Group II compared with only 7.3 in Group I. The mean time from insertion of the drug to delivery was shorter in group II (16.5 hours) than in group I (25.7 hours). There were no significant differences in the spontaneous labor rate, need for oxytocin augmentation, type of delivery, and Doppler flow velocity waveforms of the umbilical artery. The average number of required doses per patient was 1.8 in group II and 2.7 in group I. The spontaneous vaginal delivery rate was 88% in group I and 80% in group II; 6% and 10%, respectively, were delivered by cesarean section. There were no maternal complications in either group and no significant differences in perinatal outcomes such as birth weight, Apgar scores, or umbilical arterial blood gas at delivery. Although intravaginal dinoprostone is currently the drug of choice for labor induction, it is quite expensive and must be refrigerated to maintain its potency. These findings suggest that the inexpensive drug misoprostol is associated with higher Bishop scores and a shorter interval to vaginal delivery than dinoprostone. However, until large-scale studies confirm the safety of misoprostol and define an optimal dosage, it should be used with caution.