Mifepristone versus placebo to increase the rate of spontaneous labour in people with a prior caesarean: A double blind randomised controlled trial (Mi-labourTrial)

This trial — called the Mi-labour Trial — is testing whether a single dose of a medication called mifepristone can help pregnant people who have previously had a caesarean birth go into labour spontaneously. Mifepristone is a medication that works by blocking progesterone, a hormone that helps maintain pregnancy, and it is already used in other contexts. The theory is that it may gently encourage the cervix to ripen and labour to begin naturally, potentially reducing the need for formal induction of labour and the associated risks in people with a previous caesarean scar. Participants will receive either mifepristone or a placebo tablet by mouth, and neither participants nor their doctors will know which has been given (double-blind). Researchers will then track whether labour starts naturally within 48 hours, and will monitor outcomes for both the birthing person and the baby. The trial is being run across participating sites and is open to people in the final weeks of pregnancy. You may be eligible if you are pregnant with a single baby in a head-down position, have had one or two previous caesarean births, are planning a vaginal birth this time, have intact membranes, and are between 37 and 42 weeks pregnant. You are not eligible if you have had a classical (vertical) caesarean incision, have fetal growth restriction with poor blood flow on Doppler, or if induction or caesarean is already planned within the next 48 hours.