Local administration of prostaglandin E2 for cervical ripening and labor induction: the appropriate route and dose

Although there are many comparative studies concerning the local administration of prostaglandin E2 gel for cervical ripening and labor induction, the safety, efficacy and the appropriate route and dose of the gel are still debated.

One hundred and ten women with high-risk pregnancy and unripe cervix received prostaglandin E2 gel 1 mg intravaginally (n=35), 2 mg intravaginally (n=36) and 0.5 mg intracervically (n=39), maximally three times at 6-hour intervals for cervical ripening prior to labor induction. The safety, efficacy and optimal dose were assessed.

The 2 mg intravaginal gel and the 0.5 mg intracervical gel were equally effective and more effective than the 1 mg intravaginal gel in labor characteristics such as ripening time and cesarean section rate, but not in labor time. However, the failure rate (labor could not be induced) was highest in the intracervical group (10.3%) compared to the intravaginal groups (2.9% and 2.8%), although the differences were not statistically significant. In the two intravaginal groups three and five patients received the third gel application and one patient in both groups could not be induced. In the intracervical group the ripening of the cervix failed in all patients, who received the third gel. The neonatal outcome was uneventful in all groups. There were two cases of uterine hypertonus associated with fetal bradycardia, one in the intracervical and one in the 2 mg intravaginal group. Thus careful fetal monitoring is necessary. Furthermore, the vaginal route has the advantage of an easier technique of administration and obviously lower risk for inadvertent extraamnial instillation.

We recommend the use of multiple applications of 2 mg intravaginal prostaglandin E2 gel as a safe, effective and easy method for preinduction cervical ripening in high-risk pregnancies. More than three gel applications hardly increase the efficacy.