PGR and leiomyoma: Mifepristone (RU-486) has an exclusively antagonistic action on the progesterone receptor, and, as it emerged in a meta-analysis published in 2013, which included 11 RCTs where patients with symptomatic fibroids were treated with mifepristone, its use is associated with a volume reduction both in fibroids and in the uterus, and with a clinical improvement regarding symptoms [47].