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.
Who is a candidate for the procedure?
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:
They change the lining in the uterus to prevent a fertilized egg from developing any further.
They inhibit ovulation, or the release of an egg from the ovaries.
They thicken vaginal secretions to prevent sperm from traveling through the uterus to fertilize an egg.
How is the procedure performed?
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.