A randomized comparison of one single dose of vaginal 50 MCG misoprostol with 3 MG dinoprostone in pre-induction cervical ripening

Abstract

Objective: To compare the efficacy and safety of one single dose of 50 mcg misoprostol and one single dose of 3 mg of dinoprostone vaginal administration for pre-induction cervical ripening in term-pregnant women who had the indication for induction of labor but with unripe cervices. Design: A randomized double-blind controlled trial. Setting: Bangkok Metropolitan medical college and Vajira Hospital, Bangkok, Thailand. Subjects: The 143 singleton pregnant women after 37 completed weeks' gestation presented with an indication for induction of labor. All patients had a bishop score of 0-6, cephalic presentation, normal fetal heart tracing, intact membranes without uterine contraction, no contraindications for labor induction and to prostaglandins. Intervention: The subjects were stratified to either nullipara and multipara group. The subjects in each stratum were allocated by randomization with blocks of size four to receive a single dose of 50 mcg misoprostol or 3 mg dinoprostone, adminstered vaginally. After 24-hour waiting, oxytocin augmentation was given in both groups. Main outcome measure: The bishop score of cervix at 24 hours after insertion of the study drugs, the occurrence of the abnormal uterine contraction, and the number of vaginal delivery within 24, 48 hours. Results: The demographic data and the initial bishop score (median score 3.5 versus 4.0) were comparable in both groups. The change of score at 24 hours was one unit higher in misoprostol-treated patients compared to dinoprostone-treated patients (mean change score 6.5 versus 5.5; with 95% CI 0.04 to 2.1, p = 0.042) but was not of clinical importance. There was a higher frequency of hyperstilation syndrome in the misoprostol group (6.9% versus 0%) during 8 hours of cervical ripening. Although the difference was not statistically significant (p = 0.058) but was clinically important. Comparing vaginal deliveries between both groups, the frequencies of delivery within 24 hours were 46.3%versus 35.7% (p = 0.350), and within 48 hours were 88.9% versus 89.3% (p>0.05), non-significantly different. No significant difference were noted between misoprostol and dinoprostone in terms of mode of delivery, interval from start of medication to vaginal delivery, neonatal birth weight, meconium passage, 1- or 5-minute apgar score, and admission to neonatal intensive care unit. Conclusion: The efficacy of a single 50-mcg dose of vaginally administered misoprostol, is not clinically different to 3 mg dinoprostone in cervical ripening. Although the study was not sufficiently large to detect the differences in abnormal uterine contraction between two groups, there was a higher frequency of hyperstimulation syndrome in the misoprostol group compared to dinoprostone group. The close utero-fetal monitoring in misoprostol-treated patients is needed