Abstract

PIP: A prospective double-blind randomized study was undertaken to evaluate the use of RU-486 for induction of labor at term with living infants. 120 patients at 37 weeks of pregnancy or over were included. 60 were given 200 mg RU-486 per day for 48 hours and the others were given placebos. The 120 women all had a medical indication for induction of labor. In the RU-486 and placebo groups respectively, 27 and 28 were past term, 10 and 13 had preeclampsia, and 6 and 4 showed signs of intrauterine growth retardation. 75 were primiparas. Pregnancy ages ranged from 37.5 weeks to 41.4 and averaged 39.8. The uterus was scarred in 30 cases. The 2 groups were homogeneous in maternal age, pregnancy age, average parity, number of primiparas and number of scarred uterus, and average Bishop scores indicating cervical status. 3 patients in the RU-486 and 5 in the placebo group were excluded from the analysis because of deteriorating obstetrical status in the 12 hours after administration of the 1st pill. For all vaginal deliveries, the total dose in international units of oxytocin was lower in the RU-486 group: 2.41 +or- 2.4 international units, vs. 4.48 +or- 2.66 in the placebo group. The difference was also found in women undergoing caesareans, 2.97 +or- 1.82 vs 4.94 +or- 2.41 in the controls. 31 women in the RU-486 group but only 10 in the placebo group underwent spontaneous labor. It was possible to induce labor on the 4th day following administration of the 1st dose of RU-486 or placebo using prostaglandin (PG) E1 in 13 patients in each group. 13 patients in the RU-486 group and 32 in the placebo group still had Bishop scores under 4 on the 4th day. For this subgroup of 45 patients, there was no significant difference between the 2 groups in the average dose of PG E2. Indication of labor with RU-486 alone was especially successful after 40 weeks of gestation. In this series, RU-486 was successful in spontaneously inducing labor in over 80% of pregnancies around 41 weeks of gestation. There were no significant differences in the RU-486 and placebo groups in the type of delivery, average duration of labor, use of anesthetic, or neonatal condition. Maternal tolerance of RU-486 was good. There were no cases of metrorrhagia. RU-486 was shown to be useful for women with scarred uteri, in whom the use of oxytocin and prostaglandins for induction of labor remains relatively contraindicated.