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

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

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.

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.

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.