Takeaway
- Mifepristone antagonisation with progesterone should be considered experimental and may be associated with increased risk for haemorrhage.
Why this matters
- Medical abortion includes mifepristone followed by misoprostol in 24-48 hours.
- Mifepristone acts as a competitive progesterone receptor antagonist, promotes decidual necrosis, enhances uterine sensitivity to prostaglandins, and softens the cervix.
- Abortion opponents offer progesterone to "reverse" medical abortion; however, <0.005% of women will try to continue their pregnancy after taking mifepristone.
Key results
- 4 of 6 patients in the progesterone group and 2 of 6 in the placebo group had a continuing pregnancy at 2 weeks.
- Of the 4 pregnancies that did not continue, 1 had an uncomplicated suction aspiration because of no cardiac activity and 3 required ambulance transport because of severe bleeding.
Study design
- Planned double-blind, placebo-controlled, randomised trial in 2019.
- Women seeking a surgical abortion at ≤63 days gestation who agreed to delay by 2 weeks were included; study was discontinued after enrollment of 12 patients because of safety concerns.
- Mifepristone was administered followed by progesterone vs placebo starting 24 hours after mifepristone.
- Primary outcome was continuation of pregnancy.
- Funding: Society of Family Planning Research Fund.
Limitations
- Study had to be discontinued prior to completion.
References
References
