What are birth control shots?
The hormone progestin can be delivered to a woman's body through an injection. Depo-Provera, approved by FDA in 1992, is injected by a health professional into the 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, in large part because it requires little effort for the woman to comply: She simply has to get an injection by a doctor once every three months.The benefits are similar to those of the minipill and another progestin-only contraceptive, Norplant. Side effects are also similar and can include irregular or missed periods, weight gain, and breast tenderness.
Contraceptives
Resource Center
Depo-Provera:
The Quarterly Contraceptive
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Adapted from the United States Office on Women's Health in the Department of Health and Human Services.

