A recent study published in The Lancet Infectious Diseases drew attention and controversy this month because of its finding that women using injectable types of contraception (known by the brand name Depo Provera) had twice the risk of acquiring HIV from their infected partners.
Heterosexual couples in which one partner had HIV were studied in seven African countries. The participants were sexually active, not pregnant, and not on antiretroviral medicines. Women were HIV-tested quarterly and asked at those times about their contraceptive use.
The researchers found that unprotected sex and sex with other partners was more likely when women used a hormonal contraceptive, but even when they controlled for this, the risk of HIV infection was higher in women using injectable contraceptives compared to oral or no hormonal birth control. Risk of infection in uninfected men from their infected partners was also higher.
The study was limited in that it relied on women’s self-reporting of contraception use and methods. The way participants were selected could have biased the results, and condom use was also self-reported. The study did not randomize women to a birth control method, nor was it designed from the outset as a test of HIV risk and specific types of contraceptive use. It also could not clearly evaluate any risk associated with oral birth control, because there were not enough users of the pill in the study.
Despite these limitations, there is reason to be concerned about whether there is a link between Depo Provera or its generic forms and risk of HIV infection. There are several ideas about how the drugs could potentially increase risk, but the HIV question has been around since at least 1996. That year, researchers working with monkeys and implantable contraceptives published a study suggesting increased risk of a similar virus. Researchers involved with early work on this subject have responded:
How many years has it been that the non-human primate model, and other researchers, have been warning about this and being ignored? What, 15 years now? Shocking.
It’s not like we did our work and it was published in an obscure journal. There’s absolutely no excuse for people doing contraceptive work to not have known this, and not to have taken this forward in the late ’90s. We should have had this answered [in humans] ten years ago.
Global health programs often promote long-acting methods like Depo Provera for women in areas where access to regular medical care is difficult and maternal mortality is high. These same areas often have high rates of HIV. I find it unacceptable that the question of contraceptive use and HIV risk has been around for years, and we don’t appear to be much closer to a clear answer. As Charles Morrison wrote in an accompanying editorial:
The question of hormonal contraceptive use and risk of HIV acquisition remains unanswered after more than two decades. Active promotion of DMPA in areas with high HIV incidence could be contributing to the HIV epidemic in sub-Saharan Africa, which would be tragic. Conversely, limiting one of the most highly used effective methods of contraception in sub-Saharan Africa would probably contribute to increased maternal mortality and morbidity and more low birthweight babies and orphans—an equally tragic result. The time to provide a more definitive answer to this crucial public health question is now; the donor community should support a randomised trial of hormonal contraception and HIV acquisition.
Such a trial would require careful design in order to minimize any risk to participants and to stop as soon as any increased risk of one method is clear. It might be impossible to get funding for, but we owe it to women, who deserve clear and accurate information about the potential risks of injectable and all forms of contraception.