Promising selective progesterone receptor modulators: what's new in female contraception?

Selective progesterone receptor modulators (SPRMs), such as mifepristone and ulipristal acetate (UPA), have demonstrated high efficacy and safety as single-dose treatments for medication abortion and emergency contraception (EC). Other obstetrical and gynecologic applications have emerged, both for episodic and ongoing uses. The potential of these compounds to provide estrogen-free, ongoing contraception is promising; however, the rare, but serious, hepatic injury cases seen with UPA have put at least a temporary halt to further research in this area.

This paper reviews the biophysical impacts and clinical applications of SPRMs in women's reproductive health, with a focus on the roles of mifepristone and UPA in family planning. Given the political environment, especially in the United States where these applications may be threatened, extensive description is dedicated to mechanisms of action of these agents.

Both mifepristone and ulipristal acetate are first-line options for single-use applications. There continues to be a need for estrogen-free ongoing contraception that does not have unpopular impacts on bleeding caused by contraceptive methods and for treatments for heavy menstrual bleeding. However, current restrictions on UPA limit longer term use. Perhaps other SPRMs without hepatic impacts may emerge to fill this need.