Prostaglandin E2 gel for cervical ripening and induction of labor: a critical analysis

Abstract

This report summarizes the cumulative experience of 3313 pregnancies represented in 59 prospective clinical trials in which intracervical or intravaginal prostaglandin E2 gel was used for cervical ripening before induction of labor. Results indicate that local prostaglandin E2 is superior to placebo or no therapy in enhancing cervical effacement and dilation, reducing initial induction failures, shortening the induction-delivery interval, reducing oxytocin use, and lowering the rate of cesarean section because of failure to progress. Certain advantages also exist for labor induction in the presence of a favorable cervical state. Uterine hyperstimulation or pathologic fetal heart rate patterns before oxytocin administration occur in less than 1% of reported cases and are usually dose related, self contained, and reversible with the use of beta-adrenergic tocolytic therapy. Maternal systemic effects in these low doses are negligible. Worldwide clinical experience has clearly demonstrated that prostaglandin E2 gel administered before induction of labor is of major therapeutic benefit and should become commercially available for more than investigational use.

PIP: Prostaglandin E2 gel is a useful agent for ripening and dilating the cervix. Since it is not available in the US, it must be prepared by thawing and grinding a 20 mg prostaglandin E2 suppository, mixing in a small amount of methylcelulose gel, and blending. The resulting gel is stored frozen in a 3 ml plastic syringe. The gel may be administered intracervically, intravaginally, or extraamniotically. Cervical administration of .5 mg prostaglandin E2 in 2-3 ml of viscous gel is most popular, but intravaginal administration is easiest, although it requires a higher dose (1-5 mg prostaglandin E2 in 2-10 ml of gel). The condition of the cervix is usually favorable for labor induction within 12 hours (range 4-24 hours). 59 clinical trials were conducted among 3313 pregnancies. In patients with unfavorable cervix induction of labor was successful in 83% of those treated with the gel but in only 53% of untreated patients. In women with an unfavorable cervix the gel is more effective if administered intracervically. In patients with favorable cervix, 66% of nulliparas and 82% of multiparas were delivered without oxytocin. Prostaglandin E2 gel has been used successfully even in women with prolonged pregnancy, hypertension, ruptured membranes, and fetal death. It can also be used to induce late 1st trimester abortion. Side effects of the gel are mild and minor. Prostaglandin E2 gel has thus been shown to effect cervical ripening and dilatation, reduce induction failures, shorten the induction-delivery interval, reduce oxytocin use, and lower the need for cesarean sections. Prefabricated prostaglandin E2 delivery systems should be approved by the Food and Drug Administration for commercial use.