Hormone contraceptives may increase HIV risk

HIV changed the landscape of sexual relationships, making condoms a more ubiquitous presence in “the birds and the bees”. Once considered only a form of birth control, these prophylactics became STD control, preventing the spread of the deadly virus. However, AIDS was originally seen as a “gay disease”, and myths still run rampant today regarding the safety of being heterosexual in regards to HIV and AIDS. This false sense of security is even more dangerous for women on birth control.

Contraceptives and HIV

Since at least 1996 researchers have known that progestin, a synthetic form of progesterone, somehow increases an individual’s risk of contracting HIV. The simian version of HIV, SIV, more easily infects monkeys treated with progestin than those who are not (7-fold difference in infection rate). The advice then is the same as it is now – even if the woman is taking birth control pills the couple should use condoms, as it is not a matter of preventing pregnancy, but preventing disease. In addition, over the years speculation has circulated around the large number of heterosexual women who become infected by partners who are not completely honest about their sexual history (a trend called “on the down low”), so this advice is particularly important in a modern context.

HIV and birth control in Africa

Africa is the epicenter of the AIDS epidemic, with sub-Saharan Africa being home to nearly two-thirds of all HIV infections according to Avert. One problem is a lack of testing and treatment, which has made the endeavor to educate the population on condom use so important. The efforts of groups like UNAIDS and the World Health Organization (WHO) have met resistance from local governments and the Vatican, Roman Catholicism being a major religion of the continent.

Researchers studying more than 3700 couples in sub-Saharan Africa found that women who used a popular injectable birth control containing progesterone (brand name Depo-Provera from Pfizer) were twice as likely to be infected with HIV. Another problem they identified was that HIV-infected women who used the birth control were also more likely to transmit the virus to their uninfected male partners. The results were published in the journal Lancet Infectious Diseases in 2011, and more recent research has had similar results. The results may have been surprising to the general public, but not to AIDS researchers who have conducted a number of studies with the same outcome.

How progesterone increases risk

One current theory, as noted by Meredith Wadman of Nature News, is that, because increased progesterone levels thin the vaginal mucosa, the virus penetrates more easily in both directions. Another theory is a lack of Lactobacillus and other microbiota that naturally occur in the female reproductive tract. Progesterone can affect these levels, allowing the virus to survive when it would normally have been killed. Yet another theory is that the hormone increases the number of HIV-susceptible immune cells in the vaginal lining.

What this means

The key conclusion from 15 years of research is that condoms are not just birth control. Couples who are uncertain of their HIV status, couples who know that one partner is HIV-positive, and anyone partaking in casual sex should be using condoms to prevent spreading the virus even if they are using hormonal contraceptives.