The invention is directed to a pharmaceutical composition comprising a progesterone receptor antagonist namely (11beta,17beta)-17-Hydroxy-11-[4-(methylsulphonyl)phenyl]-17-(pentafluoroethyl)estra-4,9-dien-3-one for the treatment and / or prophylaxis of Uterine Fibroids (myomas, uterine leiomyoma) that is administered to a patient diagnosed with Uterine Fibroids following a specific regimen. Additionally, the invention is directed to a method for treating Uterine Fibroids (myomas, uterine leiomyoma) and / or for reducing Uterine Fibroids (myomas, uterine leiomyoma) size and symptoms related to Uterine Fibroids following a specific regimen as well as treatment of Heavy Menstrual Bleeding (HMB).