- Design
- Systematic review and meta-analysis of 15 randomised trials
- Population
- 1,874 women with singleton pregnancies at 37 weeks or more undergoing induction
- Primary outcome
- Caesarean delivery
- Effect
- 33.1% vs 41.9%; OR 0.67 (95% CI 0.54-0.82)
This systematic review pooled 15 randomised trials of mifepristone given before induction of labour in singleton pregnancies at 37 weeks or more. In all, 1,063 women received mifepristone at a range of doses and 811 received a control method. Trials of termination, fetal death and preterm induction were excluded.
Caesarean delivery occurred in 33.1% of the mifepristone groups and 41.9% of controls (OR 0.67, 95% CI 0.54-0.82). The direction held when the analysis was limited to placebo-controlled and higher-quality trials (OR 0.58, 0.40-0.83). Women given mifepristone had higher Bishop scores at 24 hours, shorter induction-to-delivery intervals and needed less prostaglandin and oxytocin.
The gap is in safety. No differences were seen in postpartum haemorrhage, neonatal unit admission or low Apgar scores, but most trials did not report these outcomes, so absence of a signal is not proof of safety. Dosing regimens varied, and the review cannot say which dose is best.
In practice this is a reason to watch for mifepristone in induction protocols and trials, not to improvise a regimen. Check its licensed indications and your unit's protocol before using it for term ripening.
- Mifepristone before term induction was linked to a caesarean rate of 33.1% vs 41.9% in pooled trials.
- Expect a more favourable cervix at 24 hours and less need for prostaglandin or oxytocin.
- Haemorrhage and neonatal outcomes were reported in only a minority of trials — safety data are thin.
- Doses varied across trials; there is no agreed regimen to copy from this review.
- Check licensed indications and your unit protocol before using it for term ripening.
Why it matters
An oral ripening agent that also lowers caesarean odds would change how units sequence induction for the unfavourable cervix.
Don't overread it
Most trials did not report haemorrhage or neonatal outcomes, so this does not establish safety.
The statistics, in plain English
An odds ratio of 0.67 means the odds of caesarean were about a third lower with mifepristone. The interval (0.54-0.82) stays below 1, so chance is an unlikely explanation. That the effect held in the placebo-controlled, higher-quality trials matters, because small, open trials tend to exaggerate benefit.
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