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Injected contraceptives are given once every 3 months. Most injectables are progestin-only. In the United States, depo-medroxyprogesterone acetate (Depo-Provera) is the only approved injected contraceptive. Depo-Provera (also called Depo, or DMPA) uses a progestin called medroxyprogesterone.
Depo-Provera is very effective in preventing pregnancies. About 3 in 100 women who use it become pregnant. However, Depo also carries the risk for many mild and serious side effects. The most serious side effect is loss of bone density (see "Disadvantages"). Because of this complication, Depo-Provera should not be used for longer than 2 years.
- A physical examination is necessary before beginning the injections.
- Depo is injected into a muscle in the patient's arm or buttock. During months between injections, the hormone slowly diffuses out of the muscle into the bloodstream.
- Depo requires an injection by the doctor once every 3 months.
- If more than 2 weeks pass beyond the regular injection schedules, the woman should have a pregnancy test before receiving the next injection.
Because Depo-Provera does not contain estrogen, it is safe for many women who may be riskier candidates for combination oral contraceptive use, such as women over age 35, women with high blood pressure, obese women, and smokers.
Depo-Provera should not be given to women who have a history of:
- Current or past breast cancer
- Stroke or blood clots
- Liver disease
- Epilepsy, migraine, asthma, heart failure, or kidney disease (due to the fact that the drug causes fluid retention)
- Unexplained vaginal bleeding
- Risk for osteoporosis
Because of the long lag time between ending treatments and restoration of fertility, Depo-Provera is not recommended for women who are thinking of becoming pregnant within 2 years.
Advantages of Depo-Provera
- Provides highly effective reversible protection against pregnancy without placing heavy demands on the user's time or memory.
- Does not increase risk for breast, ovarian, or cervical cancer. May protect against endometrial cancer.
- May be useful for women with painful periods, heavy bleeding (including heavy bleeding caused by fibroids), premenstrual syndrome, and endometriosis.
Disadvantages and Complications of Depo-Provera
- Weight gain. Most women gain an average of 5 - 8 pounds.
- Other common side effects include menstrual irregularities (bleeding or cessation of periods), abdominal pain and discomfort, dizziness, headache, fatigue, nervousness.
- Most users of Depo-Provera stop menstruating altogether after a year. Depo can cause persistent infertility for up to 22 months after the last injection, although the average is 10 months.
- Long-term (more than 2 years) use of Depo-Provera can cause loss of bone density. Depo-Provera’s label warns that the decline in bone density increases with duration of use and may not be completely reversible even after the drug is discontinued. The FDA recommends that Depo-Provera should not be used for longer than 2 years unless other birth control methods are inadequate. Some studies indicate that this bone loss may be reversible once Depo-Provera use is discontinued. Some doctors recommend that women take calcium and vitamin D supplements while on Depo-Provera.
- The injections do not provide protection against sexually transmitted diseases.
Review Date: 09/28/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.