By Kim Smiley

A recent study has brought to light some disturbing news for women using injectable contraceptives.  The study, published October 4, 2011, has discovered that the transmission rate of HIV is nearly doubled for both women who use injectable hormones for contraception and their partners.  Specifically, the rate of HIV transmission for women is 6.61 per 100 people per year when using injectable contraceptives, compared to 3.78 for those who do not.  For men whose partners use injectable contraceptives, the rate is 2.61, compared to 1.51 whose partners do not use injectable contraception.

This study may have profound implications.  More than 12 million women in eastern and southern Africa use injectable contraceptives.  Their popularity is likely due to the cost and convenience of the once-quarterly shots, used to prevent unintended pregnancies, long an issue for maternal health in the developing world.  Although the injectable contraception is not meant to prevent transmission of HIV and other sexually transmitted diseases, the hormones (namely progestin) in the injectables appear to cause a biological change that actually increases the rate of HIV infection ABOVE that of using no contraception at all.  Previous studies have also suggested this is the case, and have found that pregnancy also increases the rate of HIV.  Birth control pills (taken once daily) may also increase the risk, though so far the increase is statistically insignificant, possibly because daily pills involve   much smaller amounts of hormone.  (Although the increased transmission risk is true for all who use injectable contraception, the focus is on sub-Saharan Africa because of the high rate of HIV.)

The World Health Organization (WHO) will be reconsidering its contraception recommendations as a result of this study.  Woman using contraceptives are unlikely to use additional means of preventing HIV infection so wide spread use of a birth control method that doubles the risk of HIV infection creates a very real, global health risk.  However, the risk of death or serious health issues from unintended pregnancy have still not decreased, leading health officials unsure what the best path forward will be.  Removing an effective pregnancy control without other equally attractive options could leave more women at risk.  Officials at WHO will be working through this issue to see if both health risks from unintended pregnancy and HIV transmission can be minimized together.  It will be a tough job, but the lives of millions are at stake.

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