Medroxyprogesterone contraceptive injections are given to prevent pregnancy and, in some cases, to treat the pain associated with endometriosis. The medroxyprogesterone tablet, meanwhile, is commonly used to treat menorrhagia (unusually heavy or prolonged vaginal bleeding), as well as abnormal menstruation. It can help regulate the menstrual cycles of women who are not pregnant or undergoing menopause but have not menstruated for six months. It can also reduce the risk of uterine cancer for women who are taking estrogen. Medroxyprogesterone works by stopping the growth of the uterine lining and causing the uterus to produce certain hormones.