Misoprostol for cervical ripening at and near term--a comparative study.

Objective: To compare the safety and efficacy of misoprostol with that of dinoprostone for the induction of labour at term, or near term.

Methods: Three hundred and ninety-six women with term pregnancies were randomised to receive either oral or vaginal misoprostol, or dinoprostone. Women who had had a previous caesarean section (CS) or those with a malpresentation or who were parity > or = 5, were excluded. The control group received dinoprostone 1 mg inserted in the posterior fornix and repeated 6-hourly to a maximum of three doses. The study group received either oral misoprostol 20 micrograms 2-hourly to a maximum of four doses (80 micrograms), or vaginal misoprostol 25 micrograms in the posterior fornix with a switch to the oral misoprostol regimen if there was no change in the Bishop's score or no palpable uterine contractions.

Results: There was no significant difference in vaginal delivery rate within 24 hours between the groups (58.1% v. 58%, p = 0.633). There were no significant differences in CS rates between the groups; however, more CSs were performed for fetal distress in the misoprostol group than in the dinoprostone group (28% v. 25%). There was a significantly higher incidence of hyperstimulation in the vaginal misoprostol group (21.4%) than in the other two groups (oral misoprostol 16.5%, dinoprostone 8.9%) (p = 0.004). The incidence of meconium staining of liquor was comparable between the groups.

Conclusions: In selected women, the efficacy of misoprostol for the induction of labour at term is similar to that of dinoprostone but misoprostol is associated with a higher incidence of hyperstimulation.