Use of mifepristone to ripen the cervix and induce labor in term pregnancies. Induction of labor with mifepristone--a randomized, double-blind study versus placebo. Cervical ripening with mifepristone before labor induction: a randomized study. Mifepristone for preinduction cervical ripening beyond 41 weeks' gestation: a randomized controlled trial. A randomized comparison of oral mifepristone to intravenous oxytocin for labor induction in women with prelabor rupture of membranes beyond 36 weeks' gestation. Mifepristone for labour induction after previous caesarean section.
This study was undertaken to determine the efficacy of mifepristone for ripening the cervix and inducing labor in term pregnancies.
                In a double-blind placebo-controlled dose-finding study, 346 women received 50, 100, 200, 400, or 600 mg of mifepristone or placebo. The main endpoint for efficacy was the number of patients in whom labor occurred between 12 and 45 and 54 hours after treatment or who had a Bishop score 6 or greater. Maternal and fetal tolerability was also studied.
                No significant efficacy was observed whatever the dose of mifepristone. Mifepristone was well tolerated by the mother and fetus.
                Mifepristone, at doses up to 600 mg, does not induce labor within 54 hours in patients with unfavourable cervical status. To evaluate the efficacy of mifepristone in inducing labor in women with an unripe cervix, its effect on the cervix and on the status of the newborn.
                In a prospective double-blind study, 36 post-term pregnant women with a Bishop score of 5 or less received either 400 mg mifepristone (n=24) or placebo (n=12). If, 48 hours after the treatment was started, labor had not begun or the Bishop score was 5 or less, the women were given 0.5 mg prostaglandin E2 intracervically, a treatment which was repeated 12 hours later, if necessary.
                During the first 48 hours following treatment, 19 (79.2%) of the women treated with mifepristone and two of the women (16.7%) treated with placebo went into labor. In addition, one and three women, respectively, had a ripe cervix at the end of the 48h period. The overall success rate was thus 83.3% for mifepristone and 41.7% for placebo (p=0.008; OR 14.8; 95% CI 2.1-107.6). The median time from the start of treatment to delivery was also shorter (mifepristone 36h23' and placebo 53h17'). Treatment with intracervical PGE2 was needed more often after the placebo. The duration of labor, however, tended to be shorter after placebo than after mifepristone in the women who delivered vaginally. The frequencies of instrumental delivery were similar in both treatment groups. The median Apgar score was slightly lower at 1 minute (p<0.05) following mifepristone treatment, but did not differ at 5 and 10 minutes. There was no difference between the two treatment groups in the umbilical pH at delivery.
                The results of the present study show that mifepristone is a simple and effective treatment for inducing labor in post-term women with an unripe cervix. To determine the efficacy and safety of mifepristone for cervical ripening in post-term pregnancies.
                Women with post-term pregnancies and Bishop scores less than 6 were assigned randomly to mifepristone (41 patients) or placebo (42 patients). Mifepristone was given orally in a dose of 400 mg. Efficacy was assessed by change in the Bishop score within 48 hours after treatment; a score of 6 or greater was considered a "strict" success. An "extended" success rate was defined, including all patients with scores of at least 6 or those who delivered within 48 hours of treatment. Antenatal safety was assessed by fetal heart rate testing before and throughout labor. Neonatal safety was assessed by Apgar score, arterial or venous pH of cord blood, and blood glucose level during the first 48 hours. Analysis used Student t test for continuous variables, Kruskal-Wallis test for ordinal data, and chi2 for categoric variables.
                Strict success was achieved in 10 of 18 mifepristone patients (55%) evaluated for Bishop score on day 2 versus 8 of 29 placebo patients (27.5%) (P=.004). Extended success was achieved in 33 mifepristone patients (80.5%) and 21 placebo patients (50.0%) (P=.004). There were no statistical differences with regard to number of cesareans or fetal and neonatal safety.
                Mifepristone proved effective for cervical ripening and reduced the time to delivery compared with placebo, but it did not improve the rate of cesarean. Our study did not include enough pregnancies to reach conclusions about fetal or neonatal safety. To compare the effect of mifepristone with placebo on cervical ripening before labor induction in prolonged pregnancies.
                One hundred eighty women with pregnancies beyond 41 weeks and undilated, uneffaced cervices were assigned randomly to receive mifepristone 200 mg or placebo and observed for 24 hours. We then gave intravaginal misoprostol 25 microg every 4 hours or intravenous oxytocin. We expected 60% of placebo-treated and 80% of mifepristone-treated women to deliver vaginally within 48 hours.
                Among 180 subjects, 97 received mifepristone and 83 received placebo. The mean interval (+/- standard deviation [SD]) from start of induction to delivery was 2209 +/- 698 minutes for mifepristone-treated subjects and 2671 +/- 884 minutes for placebo-treated subjects (P <.001, log-transformed data). Twelve (13. 6%) mifepristone-treated women and seven (10.8%) placebo-treated women delivered vaginally on day 1 (P =.60). After 24 hours, the median Bishop score for both groups was 3 (0-11) (P =.51). One hundred thirty-one subjects required misoprostol, 65 (67.0%) were mifepristone-treated women, and 66 (79.5%) placebo-treated women (P =.06). The median (range) oxytocin dose was 871.5 (0-22,174) mU for mifepristone-treated women and 2021.0 (0-24,750) mU for placebo-treated women (P =.02). Seventy-seven (87.5%) mifepristone-treated women and 46 (70.8%) placebo-treated women delivered vaginally 48 hours after the start of treatment (P =.01). There were nine cesareans in the mifepristone group and 18 in the placebo group (P =.02). More nonreassuring fetal heart rate patterns and uterine contractile abnormalities occurred in mifepristone-treated subjects. There were no statistically significant differences in neonatal outcomes between groups.
                Mifepristone had a modest effect on cervical ripening when given 24 hours before labor induction, appearing to reduce the need for misoprostol and oxytocin compared with placebo. This study was undertaken to compare the use of oral mifepristone with intravenous oxytocin for labor induction in women with prelabor rupture of membranes (PROM) at 36 weeks' or greater gestational age.
                Sixty-five women with spontaneous PROM were randomly assigned to receive orally administered mifepristone or oxytocin infusion. Two hundred milligrams of mifepristone was administered, and subjects were observed for 18 hours, or intravenous oxytocin was administered.
                Thirty-three women received mifepristone and 32 received oxytocin. The average interval from start of induction to delivery was 1194.1 +/- 568.7 minutes for mifepristone-treated subjects and 770.8 +/- 519.9 minutes for oxytocin-treated subjects ( P = .001, log-transformed data). Of 33 mifepristone-treated subjects and 32 oxytocin-treated subjects, 25 (78.1%) and 17 (51.5%), respectively, achieved successful induction (defined as vaginal delivery within 24 hours) (relative risk [RR] 0.66, 95% CI 0.45-0.96, P = .01). There was more fetal distress in the mifepristone-treated group (9 vs 2, RR 4.36, 95% CI 1.02-18.66, P = .02), and a trend toward more cesarean births (7 vs 3, RR 2.26, 95% CI 0.64-7.99, P = .19). Eleven infants of mifepristone-treated women (33.3%) and 3 infants of oxytocin-treated women (9.4%) were admitted to the neonatal intensive care unit (RR 3.56, 95% CI 1.09-11.58, P = .02).
                Oral mifepristone administration 18 hours before oxytocin infusion did not improve labor stimulation in women with PROM near term, and was associated with more adverse fetal outcomes. To evaluate the efficacy and tolerance of mifepristone in women undergoing induction of labour at term after previous caesarean section.
                A prospective double blind placebo controlled trial.
                Thirty-two women at term (after 37.5 weeks' amenorrhea) who had had a previous caesarean delivery with a low transverse uterine incision. All women had a clear clinical indication for induction of labour with unfavourable cervical conditions (Bishop's score < 4). They were randomised to receive either 200 mg of mifepristone or placebo on days one and two of a four-day observation period.
                Thirteen women entered spontaneous labour: 11 were treated with mifepristone and two were in the control group (P < 0.01). Thirteen women, still with an unfavourable cervix on day four needed cervical ripening with vaginal tablets of prostaglandins. Of these, four had received mifepristone and nine the placebo. Mean oxytocin requirements were lower in the mifepristone group (P < 0.01) and the mean time interval between day one and start of labour was also significantly shorter in this group. Mode of delivery and neonatal outcome were similar in both groups.
                Induction of labour is facilitated in term women with prior caesarean section by the use of mifepristone. This induction agent appears safe and useful with no adverse events on the fetus or mother.
There is insufficient information available from clinical trials to support the use of mifepristone to induce labour. However, the studies suggest that mifepristone is better than placebo in reducing the likelihood of caesarean sections being performed for failed induction of labour; therefore, this may justify future trials comparing mifepristone with the routine cervical ripening agents currently in use. There is little information on effects on the baby.