Intracervical prostaglandins are effective compared to placebo, but appear inferior when compared to intravaginal prostaglandins.
Preinduction cervical ripening: a randomized prospective comparison of the efficacy and safety of intravaginal and intracervical prostaglandin E2 gel.
The purpose of this study was to compare the effectiveness and safety of vaginally administered 5 mg prostaglandin E2 gel prepared in our hospital pharmacy with a commercially available 0.5 mg intracervical prostaglandin E2 gel.
                Eighty-three patients undergoing labor induction were randomly assigned to one of two groups for cervical ripening. Either a preparation of 5 mg of prostaglandin E2 was placed vaginally or a commercially available 0.5 mg of prostaglandin E2 was placed intracervically. A maximum of three doses at 6-hour intervals was administered before oxytocin was begun.
                Among the 83 patients evaluated, 44 were given vaginal gel and 39 were given intracervical gel. No statistically significant differences were observed between the two treatment groups with respect to the incidence of spontaneous versus induced labor, need for oxytocin augmentation, gel-to-induction interval, Bishop score change, maximum oxytocin dose, maximum dilatation rate, length of labor, cesarean section rate, fetal Apgar scores, fetal umbilical vein pH, or fetal umbilical artery pH.
                The two prostaglandin E2 formulations appear equivalent in efficacy and safety. Constraints placed on intracervical prostaglandin E2 gel make the vaginal preparation a desirable choice.