Progestins lower the risk of estrogen-related cancer of the uterus. This medicine used in combination with estrogen (hormone replacement therapy - HRT) should not be used to prevent heart disease. Two drug combination HRT (estrogen and progestin menopause) can infrequently cause cancer of the breast, heart disease (e.g., heart attack), stroke, dementia, or blood clots in the lung (pulmonary embolism) or leg. Estrogens may also increase the risk of cancer of the ovary. These risks appear to depend on the length of time this combination is used and the amount of estrogen per dose. Therefore, two-drug HRT should be used for the shortest possible length of time at the lowest effective dose, so you obtain the benefits and minimize the chance of serious side effectis from long-term treatment. If you use this drug for an extended period, you should be evaluated at least once a year.
You should not use this medicine during the first 4 months of pregnancy because birth defects may occur. This medicine has not been proven to prevent natural abortions that occur early in the pregnancy. Often, the cause of an early natural abortion is due to a defective female egg. Using this drug does not fix a defective egg and may get in the way of expelling it. In males, medroxy-progesterone reduces the production of testosterone by the testes and the adrenal glands, which in some males (not all) reduces sex drive. Several states mandate use of medroxy-progesterone acetate, or MPA, for "chemical castration" of convicted rapists and sex offenders.