CONTENTS
Home (Key Points)
Injectables Today and Tomorrow
 Box: Injectables Tomorrow: Subcutaneous DMPA and Home Injection
Web Table 1. Knowledge and Current Use of Injectable Contraceptives Reported by Married Women 15–49, All Surveys 1990–2006
Web Table 2. Knowledge and Current Use of Injectable Contraceptives Reported by Married Women 15–49, Most Recent Surveys 1990–2006
Web Figure. Donor Shipments of Injectables Increasing
Supply Meets Demand With Forecasting and Ingenuity
Web Table 3. Key Resources for Program Managers and Providers
Training to Meet Demand
Box: With Training, a Range of Providers Can Give Contraceptive Injections
Give Injections and Dispose of Waste Safely
Community Programs Can Safely Increase Access to Injectables
Meeting Rising Demand Efficiently
Communication Helps Women Try and Use Injectables
Questions and Answers About Injectables
Box: Women With HIV/AIDS Can Use Injectables
Bibliography
Credits
Coming Soon: "Injectables Toolkit" Web site. Go to http://www.injectablestoolkit.org for job aids and information about injectable contraceptives.
• Table 1: Estimated Worldwide Use of Injectables Among Married Women Ages 15–49, 2006
• Table 2: Formulations, Injection Schedules, and Availability of Injectable Contraceptives
• Table 3: Key Resources for Program Managers and Providers
Tools for Program Managers
• Checklist: Good-Quality Injectables Services
• Checklist: Improving Access to Injectables
Tools for Providers are in the companion INFO Reports. See also Population Reports, "When Contraceptives Change Monthly Bleeding," Series J, No. 54, August 2006.
 Order this report
 Download PDF or PowerPoint
 E-mail this page
 See Companion INFO Reports on "Injectable Contraceptives: Tools for Providers"
See more Population Reports
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Questions & Answers About Injectables
| 1 |
How do injectables work?
Injectables work mainly by preventing the development and release of eggs from the ovaries (ovulation). They also thicken cervical mucus, which blocks sperm from meeting the egg. Both progestin-only and combined injectables are very effective when users return on time for their next injections. |
| 2 |
How are combined injectables similar to combined oral contraceptives? How do they differ?
Long-term studies of the health risks and benefits are under way, but few results are available yet. Still, combined injectable contraceptives contain the same types of hormones as combined oral contraceptives (COCs). Therefore researchers assume that most of the findings about COCs also apply to combined injectables. A difference is that monthly injectables are not processed by the liver before entering the bloodstream, as are medications taken by mouth. As a result, monthly injectables have less effect on liver function than COCs, and women can use them with some conditions, such as gall bladder disease, that would make use of COCs less safe (212). Also, short-term studies have found that monthly injectables have less effect than COCs do on blood pressure, blood clotting, and the breakdown of fatty substances (lipid metabolism). |
| Side Effects |
| 3 |
Are the bleeding changes caused by injectables harmful?
In most cases, no. Heavy bleeding, however, which is uncommon, may contribute to anemia, particularly among women who are nearly anemic. Also, if there is reason to suspect that a bleeding pattern has another cause—not the injectable—then the cause should be investigated. |
| 4 |
If a woman does not have monthly bleeding while using progestin-only injectables, does this mean that she is pregnant or that blood is building up in the body?
No. Lack of bleeding most likely does not mean a woman is pregnant if she was not pregnant when she started injectables and has been having injections on time. Blood does not build up inside a woman's body while she uses progestin-only injectables. Lack of bleeding while using injectables is similar to lack of bleeding while breastfeeding. During the menstrual cycle the lining of the womb thickens and a woman releases an egg (ovulates). If the egg is not fertilized, the tissue and blood from the thickened lining are shed as menstrual bleeding. When a woman uses progestin-only injectables or if she fully breastfeeds her baby for six months, the lining of the womb does not thicken, the woman usually does not ovulate, and there is no menstrual bleeding. |
| 5 |
Will injectables change mood or sex drive?
Some women using injectables report mood changes and less sex drive, but the great majority do not (65, 87, 202). It is difficult to tell whether such changes are due to injectables or to other causes. There is no evidence that using injectables changes a woman's sexual behavior. |
| Safety |
| 6 |
Will a woman still be able to become pregnant after she stops using an injectable?
Yes. Monthly bleeding and release of eggs from the ovaries (ovulation) return. Women of any age, whether or not they already have children or want more children, can use any injectable contraceptive, and it will have no effect on future fertility. |
| 7 |
Do injectables cause cancer?
Many studies show that DMPA does not cause cancer. DMPA use helps protect against cancer of the lining of the uterus (endometrial cancer). Women have a slightly increased risk of being diagnosed with breast cancer while using DMPA or shortly after they stop, but this may be due to earlier detection of existing disease. If a woman has not developed breast cancer within five years of starting DMPA, then her risk of breast cancer is the same as the risk for a similar woman who never used DMPA.
A few studies suggest that there may be a slightly increased risk of cervical cancer among women who use DMPA for five years or more if they have persistent infection with certain strains of human papillomavirus (HPV) (178). Cervical cancer cannot develop because of DMPA use alone. It is caused by persistent infection with these strains of HPV. While HPV infection is common, persistent HPV infection with one of the cancer-causing strains is not common. Few additional cases of cervical cancer will occur because of DMPA use.
Little information is available about NET-EN. It is thought to be as safe as DMPA and other contraceptive methods containing only a progestin, such as progestin-only pills and implants. |
| 8 |
Can injectables cause abortion?
No. Injectables do not disrupt an existing pregnancy. They should not be used to cause abortion. They will not do so. |
| 9 |
Do injectables cause birth defects?
No. DMPA does not cause birth defects even if a woman mistakenly receives an injection when she is pregnant or even if a woman becomes pregnant while using DMPA (131). There is little evidence about NET-EN, but it is assumed to be the same as DMPA in this regard.
Combined oral contraceptives do not cause birth defects, and so it is assumed that combined injectables do not cause birth defects, either (26, 131, 155). |
| 10 |
Why does DMPA affect bone density?
DMPA reduces levels of estrogen in the body. Estrogen helps to regulate the flow of minerals to and from the bones. When estrogen levels are low, more minerals are lost from bone than are reabsorbed. This leads to a decrease in bone density (137).
Whether DMPA increases the risk of broken bones requires more research. A woman's lifetime risk of broken bones is unlikely to be affected because women regain bone density after stopping DMPA. Among adults who stop using DMPA, after two to three years their bone density appears to be similar to that of women who have not used DMPA. Among adolescents, it is not clear whether the loss in bone density prevents them from reaching their potential peak bone mass. Also, more research is needed on the effect of DMPA use during the reproductive years on the risk of broken bones during menopause, and the effect of DMPA use near menopause on a woman's ability to regain lost bone density.
Because of the bone loss issue, drug regulatory agencies in the United Kingdom and United States advise women to consult providers after using DMPA for two years to decide if they want to continue DMPA or to choose another method (49, 193). An expert working group advising the World Health Organization, however, concluded that the decrease in bone density should not limit who uses DMPA, or for how long, among women ages 18 to 45. The benefits of using DMPA outweigh the theoretical concerns about bone fracture for these women and for adolescents younger than 18 and women over 45. Since there is not enough information about long-term DMPA use by adolescents and women over 45, the expert group recommended that providers and these women reconsider the benefits of DMPA and their risk of bone fracture over time. These recommendations also apply to NET-EN (216). |
| Other Uses |
| 11 |
Can a single injection of a combined injectable be used to bring on regular monthly bleeding in a woman with irregular bleeding?
No. A woman may experience some bleeding (a "withdrawal bleed") about a month later as a result of the injection, but there is no evidence that giving one injection of a combined injectable to a woman with irregular bleeding will cause her monthly bleeding to become regular. |
| 12 |
Can a single injection of a combined injectable be used as a pregnancy test?
Giving a woman combined injectables to see if she has bleeding when she stops taking them is not recommended as a way to tell if she is pregnant. Combined injectables should not be given to a woman as a "hormonal pregnancy test" because they do not produce accurate results. |
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