Objective: To evaluate the efficacy and tolerance of mifepristone in women undergoing induction of labour at term after previous caesarean section.
Design: A prospective double blind placebo controlled trial.
Subjects: 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.
Results: 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.
Conclusions: 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.