Objective: To determine whether outpatient administration of intracervical prostaglandin (PG) E-2 gel decreases the interval to delivery and duration of labor. Methods: A randomized, double-blind, placebo-controlled trial compared the intracervical placement of 0.5 mg PGE(2) gel with placebo in 61 pregnant women at 38 weeks' or greater gestation with Bishop scores less than 9. Transvaginal cervical length, fetal fibronectin, and Bishop score were assessed before gel placement. Subjects were then allowed to go into spontaneous labor unless an indication for induction developed. Results: Thirty women were assigned to PGE(2) and 31 to placebo. There were no significant demographic differences between the groups and there were no differences in cervical length, fetal fibronectin status, or Bishop scores. Fifteen women in the PGE(2) group and five in the placebo group went into labor and delivered within the first 2 days after gel placement (P = .007). The median interval to delivery was significantly shorter in the PGE, group, at 2.5 days, compared with placebo, at 7 days (P = .02). Nulliparas in the PGE(2) group had a median interval to delivery of 2 days, compared with 7 days for nulliparas receiving placebo (P = .03). Active phases of labor were significantly shorter in the PGE(2) group and for women with a negative fetal fibronectin test who received PGE(2). Conclusion: Outpatient administration of intracervical PGE(2) gel shortened intervals to delivery and shortened labor. (C) 1999 by The American College of Obstetricians and Gynecologists.