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A new study finds that the use of a hormonal contraceptive popular with women in eastern and southern Africa doubles their risk of becoming infected with HIV. And when it is used by HIV-infected women, it doubles the risk they will infect their male partners. The large study was conducted in sub-Saharan Africa, where HIV - the virus that causes AIDS - has been spread mainly through heterosexual sex.
For those women in sub-Saharan Africa who use a hormonal type of birth control, the most popular form is a hormone shot. It allows them to space their children, does not require travel to a doctor and is effective for three months at a time. But now, a significant new study shows this method of birth control could be helping to spread HIV and AIDS across a continent with the biggest HIV-infected population on the planet.
The study involved nearly 4,000 heterosexual couples from sub-Saharan Africa. In each couple, either the man or the woman was already infected with HIV. The researchers tested the couples for HIV over a two-year period. The results: non-infected women getting the birth-control shots had double the risk of getting HIV. And the healthy men whose female partners had HIV were twice as likely to become infected.
One of the researchers - Renee Heffron from the University of Washington - spoke to us from Kenya via Skype.
"It's really important that women continue to use hormonal contraceptives, but that they understand the importance of using condoms when they are using hormonal contraceptives, and that hormonal contraceptives don't protect them against HIV, and in fact, may increase their risk."
Hormonal contraception includes both birth control pills and injections, but this study focused on injectable contraceptives. The researchers said their findings were the same for women who used birth control pills, but that sample was very small, and more studies need to be done.
The study included only women from Africa, but it's likely the results could apply to women in other regions as well. The World Health Organization has called a meeting in January to evaluate the study and re-think its advice to women about hormonal contraceptives. Pfizer, the drug company that makes the branded version of the hormone shot, has been quoted as saying it is reviewing the study. Pfizer officials were not immediately available for further comment.