Progestin injections are shots of a type of progestin that is given to women for birth control. Medroxyprogesterone acetate is the progestin used in these shots. It is similar to the female hormone progesterone that the body naturally produces.
Progestin injections are often used as birth control, to prevent pregnancy. They are also used to control heavy or irregular menstrual bleeding. Progestin injections also decrease a woman's risk for uterine cancer.
Progestin injections prevent pregnancy in these ways:
Progestin injections are generally given in the muscle of the buttocks or upper arm. A single shot provides birth control for 12 weeks. It can be repeated if the woman wishes to continue birth control. It is very important for a woman to get these shots exactly every 12 weeks. The shots are less effective in preventing pregnancy if the time between shots is more than 12 weeks. Shots may be given more often if they are used for heavy or abnormal menstrual bleeding.