Induction of labor using high-dose or low-dose prostaglandin vaginal pessaries

Two hundred women were studied in a randomized controlled trial of induction of labor using high-dose (3 mg) or low-dose (0.5 mg) prostaglandin E2 vaginal pessaries. Induction using 3-mg pessaries was more successful, with a shorter overall induction-delivery interval and less requirement for analgesia, although uterine hyperstimulation occurred in two patients. In contrast, the low-dose regimen did not cause hypertonus and, though less successful in inducing labor, the total dose of prostaglandin E2 used was considerably less than in the 3-mg group. The cesarean section rate when the cervix was initially unfavorable was high in both groups (high dose 18.2%, low dose 16.7%). The response to prostaglandin E2 did not relate closely to the initial cervical state.