Importance: Mifepristone (RU-486) is a selective progesterone receptor modulator that has antagonist properties on the uterus and cervix. Mifepristone is an effective abortifacient, prompting limitations on its use in many countries. Mifepristone has many uses outside of induced abortion, but these are less well known and underutilized by clinicians because of challenges in accessing and prescribing this medication.
Objectives: To provide clinicians with a history of the development of mifepristone and mechanism of action and safety profile, as well as detail current research on uses of mifepristone in both obstetrics and gynecology.
Evidence acquisition: A PubMed search of mifepristone and gynecologic and obstetric conditions was conducted between January 2018 and December 2021. Other resources were also searched, including guidelines from the American College of Obstetricians and Gynecologists and the Society of Family Planning.
Results: Mifepristone is approved by the Food and Drug Administration for first-trimester medication abortion but has other off-label uses in both obstetrics and gynecology. Obstetric uses that have been investigated include management of early pregnancy loss, intrauterine fetal demise, treatment of ectopic pregnancy, and labor induction. Gynecologic uses that have been investigated include contraception, treatment of abnormal uterine bleeding, and as an adjunct in treatment of gynecologic cancers.
Conclusions and relevance: Mifepristone is a safe and effective medication both for its approved use in first-trimester medication abortion and other off-label uses. Because of its primary use as an abortifacient, mifepristone is underutilized by clinicians. Providers should consider mifepristone for other indications as clinically appropriate.