Medroxyprogesterone acetate is a hormonal steroid that is also classified as a synthetic progesterone-like substance. It acts to convert the proliferative phase of the endometrium (the lining of the uterus) into secretory phase. It has no estrogen-like effects and it has the ability to inhibit pituitary hormones, thus it prevents the maturation of follicles and ovulation. It is available as an oral tablet or as an injectable drug.