Contraception – Hormonal Injection


  • The goal of contraception (or birth control) is to prevent an unplanned pregnancy. The majority of methods of contraceptions enable sexually active couples to temporarily avoid pregnancy. Permanent birth control is accomplished through sterilization. Be sure you know and understand the different types of birth control available to you, the risks and benefits of each, and any side effects, so that you can make an informed choice.
  • The most widely used injectable form of birth control is the hormone medroxyprogesterone (Depo-Provera). The regimen consists of an injection every 90 days. It suppresses ovulation to some extent makes the mucus of the cervix unable to be penetrated by viable sperm and renders the lining of the uterus unreceptive to a fertilized egg.


  • Is very effective for birth control (over 99%); one of the most effective forms available.
  • Quickly and easily administered by a health care provider.
  • The hormone used, progestin, provides a birth control option for women who cannot take estrogen hormones that are used in oral contraceptives.
  • The injections require no daily routine.
  • Freedom from concern and enjoyment of spontaneous sexual intercourse.
  • Future fertility does not appear to be affected, but it may take several months to 1 year for ovulation to occur once the injections are discontinued.


  • Presence of other medical problems may affect the use of these injections. These include allergies, liver disorder, cancer or a history of cancer, diabetes mellitus, epilepsy, unexplained vaginal bleeding, other bleeding problems or stroke.
  • Side effects or adverse reactions can include irregular uterine bleeding, cessation of menstrual periods (amenorrhea), headaches, fluid retention, weight gain, bleeding disorders, skin reactions to the injections.
  • Some women find that the injections may lead to depression, fatigue, nervousness and loss of sexual desire.
  • Bone mineral density may be reduced.
  • Normally not recommended for breast-feeding women.
  • Does require injections every 3 months in a health care provider’s office.
  • Cannot be reserved as easily discontinuing a daily pill.
  • Long-term effects are still being studied.


  • The injections will be prescribed for you after the health care provider has studied your medical history and the results of a physical examination.
  • The first injection is often given during the first 5 days of the menstrual period so that pregnancy has been ruled out.
  • The injections are injected into a muscle once every 3 months (usually a large muscle such as the buttocks muscle is used). The contraceptive levels of hormone persist for up to 4 months (allowing 2 to 4 weeks margin of safety).
  • Follow-up medical examinations are recommended at least once a year; may be done more frequently.


There may be some interaction with other medications. Advise any health care provider treating you or prescribing for you that you have these hormone injections.