Selective progesterone receptor modulators: new possibilities for gynecologic hormone therapy.

Progesterone regulates several female reproductive functions. Progesterone and synthetic progestins derived from it have long been utilized in gynecology. The effects of these steroids in target cells are mediated via progesterone receptors, Progesterone receptors are also the target of action of selective progesterone receptor modulators. Of the molecules of this newer group of drugs, two are presently in clinical use. Mifepristone is used in nonsurgical abortion, in softening of the cervix before surgical abortion, and in the induction of labor in cases of intrauterine death. The indications of ulipristal acetate are postcoital contraception and treatment of uterine myomas and the resulting symptoms.