Contraceptive, injectable progestin: Injectable progestin (Depo-Provera) was approved by the U.S. Food and Drug Administration (FDA) for contraception in 1992. It is injected by a health professional into the woman's buttocks or arm muscle every three months.
Depo-Provera prevents pregnancy in three ways: It inhibits ovulation, changes the cervical mucus to help prevent sperm from reaching the egg, and changes the uterine lining to prevent the fertilized egg from implanting in the uterus.
The progestin injection is extremely effective in preventing pregnancy. It also can decrease menstrual bleeding and cramps as well as lower the risk for endometrial and ovarian cancer and pelvic inflammatory disease. Side effects can include irregular or missed periods, weight gain, and breast tenderness.