As if the AIDS crisis in Africa wasn't bad enough, scientists now believe that a birth control method that's popular in the eastern and southern parts of the continent is increasing women's HIV risk. A major peer-reviewed study found that women who get a hormone shot every three months double their risk of becoming infected with HIV, and the male partners of HIV-positive women are twice as likely to conract the disease.
The study involved 3,800 couples in Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia, according to The New York Times. Researchers from the University of Washington followed each couple, in which one partner was HIV-positive, for two years and tracked their contraception methods and whether the other partner became infected. The rate of infection for women using hormonal contraception was 6.61 per 100 person-years, compared with 3.78 for those who didn't use the shot. Infected women using the shot transmitted HIV to their male partners at a rate of 2.61 per 100 person-years, compared with 1.51 for those who didn't use the contraception.
The women in the study were all African and were probably using the generic version of the shot, but presumably the effect is the same for everyone who uses injectable birth control, including the brand name Depo-Provera. Obviously this is concerning for all women who use the product, but researchers are focusing on Africa because the rate of HIV transmission among heterosexual couples is much higher there, and the shot is used more widely. In the U.S. only 3% of women are on the contraceptive shot, but in sub-Saharan Africa it's used by 6% of women between the ages of 15 and 49, or about 12 million women.
Birth control is often hard to come by in the region, so health officials are hesitant to issue a warning that could discorage women from using the shots. Particularly because they don't understand how the shot promotes HIV infection. According to one untested theory, the progestin in the shot may cause changes in the vagina and cervix that increase HIV's ability to replicate. The most obvious explanation is that couples are less likely to use condoms if the woman is on birth control, but the researchers recorded data on condom use and concluded that isn't what's increasing the infection rate.
The World Health Organization will meet in January to decide if it should issue a warning about the link between injectable birth control and HIV, but it's a difficult call. Ideally, health officials would recommend using condoms along with other methods like IUDs and implants, but the reason so many women are on the shot in the first place is that it's often the only easily accessible and affordable birth control option. Isobel Coleman, director of the women and foreign policy program at the Council on Foreign Relations, says:
"The best contraception today is injectable hormonal contraception because you don't need a doctor, it's long-lasting, it enables women to control timing and spacing of birth without a lot of fuss and travel ... If it is now proven that these contraceptions are helping spread the AIDS epidemic, we have a major health crisis on our hands."
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