Medroxyprogesterone acetate (MPA), also known as depot medroxyprogesterone acetate (DMPA) and sold under the brand name Depo-Provera among others, is a hormonal medication of the progestin type. It is used as a method of birth control and as a part of menopausal hormone therapy. It is also used to treat endometriosis, abnormal uterine bleeding, abnormal sexuality in males, and certain types of cancer. The medication is available both alone and in combination with an estrogen. It is taken by mouth or by injection into a muscle or fat.Common side effects include menstrual disturbances such as absence of periods, abdominal pain, and headaches. More serious side effects include bone loss, blood clots, allergic reactions, and liver problems. Use is not recommended during pregnancy as it may harm the baby. MPA is an artificial progestogen, and as such activates the progesterone receptor, the biological target of progesterone. It also has weak glucocorticoid activity and very weak androgenic activity but no other important hormonal activity. Due to its progestogenic activity, MPA decreases the body's release of gonadotropins and can suppress sex hormone levels. It works as a form of birth control by preventing ovulation.MPA was discovered in 1956 and was introduced for medical use in the United States in 1959. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.59–1.57 per vial. In the United Kingdom this dose costs the NHS about 6.01 pounds. In the United States it costs less than $25 a dose as of 2015. MPA is the most widely used progestin in menopausal hormone therapy and in progestogen-only birth control. DMPA is approved for use as a form of long-acting birth control in more than 100 countries.