HIV transmission rates may be increased by hormone contraceptive use,… (Corbis )
Use of hormonal contraceptives may double the risk of catching or transmitting HIV-1 (the most common and dangerous strain of HIV), according to a new study of thousands of heterosexual couples in sub-Saharan Africa.
In each case, just one of the couple -- the woman or the man -- was HIV-positive. Some took hormonal contraceptives and some didn’t. The 3,790 couples in seven countries were tracked for about 18 months, and the rates at which the other member of the couple became HIV-positive were carefully noted.
The finding, published online in the journal Lancet Infectious Diseases, isn't definitive and mostly tests the injected contraceptive DMPA (Depo-Provera), which is much more commonly used in sub-Saharan Africa than oral contraceptives. But it does gel with suggestions from earlier studies.
Study authors Renee Heffron of the University of Washington in Seattle and colleagues said they'd ruled out the most obvious way that hormonal contraceptives could raise the risk for HIV — that is, reduced use of condoms. The authors said they checked rates of condom use and these didn't significantly differ between couples who used hormone contraceptives and couples who didn't.
Instead, they suggest there could be a biological reason for the difference. They found more genetic material of HIV in samples of cervical tissue from the women using hormonal contraceptives than those who weren't. So perhaps there's something about hormone use that might alter the tissue of the vagina in a way that makes HIV transmission more likely.
The authors and others do note that this study was not ideal for a variety of reasons. For one, it relied a lot on self-reporting -- participants told the researchers whether they were using hormonal contraceptives and how often they used condoms.
Also, this wasn't a gold standard clinical trial in which a researcher would randomly assign similar people to either use hormonal contraceptives or not and then track them for years and see what happened to them. Instead, the scientists tracked people who had already made that choice for themselves.
Theoretically, there could be other differences between these couples that led to the different choices and also a difference in HIV transmission rate.
Because of this and other caveats, both the study researchers and authors of an accompanying commentary say a clinical trial is urgently needed to properly investigate the link.
And even if the link is confirmed, what then? The benefits of contraception are huge for people in sub-Saharan Africa, they note.
“A separate analysis by the same study team suggests that pregnancy itself might increase the rate of HIV transmission,” write Drs. Charles S. Morrison and Kavita Nanda of the global development organization FHI 360, based in Durham, N.C., in the accompanying commentary. "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 birth weight babies and orphans -- an equally tragic result."