What Is Some Important Information About the Depo-Provera Shot?

Depo-Provera is a form of hormonal birth control for women given by injection every 12 weeks, explains Planned Parenthood. It releases the hormone progestin that prevents ovulation and thickens cervical mucus to help prevent sperm from reaching a woman's eggs.

Depo-Provera is an appropriate method of birth control for many women. However, those with a history of blood clots, breast cancer, liver disease or unexplained vaginal bleeding should not use the drug, according to WebMD. The medication can cause side effects that include changes in menstrual periods, headaches and dizziness, changes in appetite and weight gain, and nervousness or depression. It may also cause bone thinning, excessive hair growth on the face or rest of the body, and hair thinning or hair loss on the head. Of these side effects, changes to the menstrual cycle are most common.

The medication is considered a highly effective form of birth control, notes Healthline, with a less than 1 percent pregnancy risk when administered every 12 weeks. Pregnancy risk increases to 6 percent when the shot is taken less frequently. Other advantages include the discreet nature of the medication and ease of administration. For example, there are no patches or rings to place, nor pills that must be taken at the same time each day for protection against pregnancy. Additionally, when administered within seven days after the start of a woman's period, pregnancy protection is immediate.