The Essential Knowledge section of the Injectables Toolkit provides policy makers, program managers, and service providers with key, or “essential,” background and reference materials on injectable contraceptives, including fact sheets, research reports, and information briefs. You can find information about both progestin-only injectables and combined injectables. The "Essential Knowledge About Injectables" document below is a thorough summary of the current biomedical, social science, and programmatic knowledge on injectable contraceptives as of July 2010. We will update this document periodically to reflect new research findings and programmatic knowledge.

Click on the links below to access the following essential resources on injectables:

Research Reviews

Handbooks

Fact Sheets and Briefs

Community Based Access to Injectables

Have a suggested resource or comment about this section? Please email us at toolkits@k4health.org or visit our discussion board.

Key Points about Injectable Contraceptives:

• Injectable contraceptives are reversible, discreet, and highly effective, with a typical pregnancy rate of about 3% during the first year of use. Effectiveness depends on receiving reinjections on time.
• Nearly all women can safely use injectables.
• If it is reasonably certain a woman is not pregnant, no tests are necessary to begin using injectables. She can begin without a pelvic exam, blood tests, cervical cancer screening, or a breast examination.
• Injectables contain synthetic steroid hormones that are injected into a woman’s hip, upper arm, or buttocks and then slowly released into the bloodstream. These hormones prevent ovulation (the release of eggs from the ovaries); thicken the cervical mucus, which prevents sperm from meeting an egg; and suppress endometrial growth, making the uterus lining uninhabitable for a fertilized egg.
• Combined injectable contraceptives (CICs), which contain both progestin and estrogen, are administered every 4 weeks and can be given up to 7 days early or 7 days late.
• Some progestin-only injectables, which do not contain estrogen, are administered every 8 weeks (NET-EN) and can be given up to 2 weeks early or 2 weeks late. Others are administered every 13 weeks (DMPA) and can be given up to 2 weeks early or 4 weeks late. 
• There are no known health risks of using progestin-only injectables. Risks of CIC use are expected to be similar to those of combined oral contraceptives, which include blood clots, stroke, and heart attack. However, these risks are very or extremely rare.
• Bone mineral density decreases during use of progestin-only injectables but increases again when use stops.
• Health benefits of progestin-only injectables include protection against endometrial cancer, uterine fibroids, symptomatic pelvic inflammatory disease, and iron-deficiency anemia, as well as a reduction of pain related to sickle cell anemia, endometriosis, and intercourse.
• Health benefits of CICs are expected to be similar to those of combined oral contraceptives, which include protection against endometrial cancer, ovarian cancer, and pelvic inflammatory disease; possible protection against ovarian cysts and iron-deficiency anemia; and reduction of menstrual cramps, menstrual bleeding problems, ovulation pain, excess body or facial hair, symptoms of polycystic ovarian syndrome, and symptoms of endometriosis.
• Injectable contraceptives do not prevent transmission of STIs including HIV. Condoms should be used along with injectables to prevent STI/HIV transmission.
• Fertility returns after discontinuing use of injectables, but it can be delayed several months.
• Common side effects of injectables include bleeding changes and gradual weight gain.