Efficacy of outpatient induction with low-dose intravaginal prostaglandin E2 : a randomized, double-blind, placebo-controlled trial

Our purpose was to determine whether a protocol for outpatient induction is safe and effective for initiating labor. A randomized, double-blind, placebo-controlled trial was performed with 100 low-risk patients having well-dated pregnancies. Women with a Bishop score < or = 6 at 38 to 40 weeks' gestation were administered either 2 mg of intravaginal prostaglandin E2 gel or placebo for 5 consecutive days as outpatients while undergoing fetal monitoring. The median interval from randomization to delivery was 4 days in the prostaglandin E2 group (range 0 to 28 days) versus 10 days in the placebo group (range 0 to 26 days, p = 0.002). Twenty-seven of 50 patients (54%) in the prostaglandin E2 group were admitted for labor during the dosing interval compared with 10 placebo-treated patients (20%, p = 0.001). The mean gestational age at delivery was significantly reduced in the treatment group (39.9 +/- 1.0 weeks vs 40.5 +/- 0.99 weeks, p = 0.003) as was the incidence of postdates pregnancy (40% vs 66%, p = 0.016). Hyperstimulation was observed in one prostaglandin E2-treated patient, but no intervention was required. Outpatient low-dose prostaglandin E2 gel administration is effective for initiating labor in patients with an unfavorable cervix and appears safe if performed with adequate monitoring.