Women worldwide have used Depo-Provera for over 30 years. However, the United States Food and Drug Administration only approved its use about 10 years ago. Depo-Provera is a hormonal, injectable contraceptive given every 12 weeks. It is considered safer than a birth control pill because it contains only a synthetic progesterone hormone — there is no estrogen. In contrast, combined oral contraceptives (the pill) contain both estrogen and progesterone. Estrogen is associated with more serious health risks than progesterone. Progesterone-only methods are safe for use in women who, for medical reasons, cannot take estrogen. If a woman keeps her injection appointments, as scheduled, every 12 weeks, the risk of pregnancy is 0.3% in the first year of use.
Depo-Provera's mechanism of action is similar to that of oral contraceptives in that it inhibits ovulation (the release of a mature egg from the ovary). Progesterone also causes thickening of cervical mucous. This effect impedes the progress of sperm through the cervical canal. Depo-Provera has no long-term effects on fertility. However, after discontinuance of this method, it may take several months for your periods to become regular once again.
The noncontraceptive benefits of Depo-Provera use are similar to oral contraceptives and include decreased bleeding or no bleeding, decreased menstrual cramps, and no ovulatory pain.
The primary side effect of Depo-Provera is irregular bleeding. This tends to occur in the first year of use. Many women will experience some bleeding at the end of the 12 week dose interval.
By the end of the first year, 25% of women using this method will have no bleeding.
Some women are uncomfortable with irregular bleeding or no bleeding. Additional side effects are as follows:
Other minor side effects, which may be experienced on Depo-Provera are similar to those experienced by oral contraceptive users except that weight gain tends to be greater on Depo-Provera. Always discuss side effects with your health care provider.
Because Depo-Provera is a long-acting hormonal preparation (as opposed to oral contraceptives) side effects can take several weeks to resolve after discontinuance. Other important considerations regarding this method include:
Depo-Provera is a reversible, safe and effective method of birth control but it is a medication. Always tell your health care provider that you are receiving Depo-Provera injections. If you are given a prescription for another medication, be sure to ask either your health care provider or your pharmacist about possible drug interactions with Depo-Provera.
If you have any questions or if any of this information is unclear, please be sure to speak with one of the providers in the Women's Health Program. The telephone number for an appointment is 603/646-9401.
Last Updated: 3/22/10