When it comes to the double duty of preventing both pregnancy and HIV, condoms are the best option, especially in the developing world where treatment for the infectious disease is harder to access. But the same isn’t true of other contraceptive methods, according to the latest study in Lancet Infectious Diseases.
Lauren Ralph, an epidemiologist at University of California San Francisco, and her colleagues conducted a review of all of the available studies on hormonal contraceptive methods—including injections of Depo Provera and Net-En that work to prevent pregnancy for about 12 weeks, as well as the pill. Among 12 studies involving nearly 40,000 women in sub-Saharan Africa, those using Depo showed a 40% higher risk of getting HIV than those using other methods or no contraception at all.
Previous studies suggested that Depo, which is made up of a hormone that mimics the reproductive hormone progesterone, was linked to higher risk of infection, but other studies showed conflicting results. Ralph found that only Depo was associated with a higher risk of HIV infection; there was no similar increase among women using the pill, which is composed of two hormones, estrogen and a form of progesterone. The correlation remained even after they considered potentially confounding factors, such as the women’s condom use.
While the study didn’t address the reason for the difference between oral contraception and Depo, some research suggests that their differing hormone combinations may have varying effects on the structure of the genital tract, a woman’s immune response or her vaginal flora, all of which could influence her vulnerability to acquiring HIV.
The results raise a difficult question about whether the increased risk of HIV infection warrants removing Depo from a woman’s contraceptive options in places like Africa. Worldwide, according to the authors, 41 million women use injectable contraception, and they have played a role in lowering death and health complications among women of child-bearing age. “Whether the risk of HIV observed in our study merits complete withdrawal of hormonal contraception, especially Depo, needs to be balanced against the known benefits of highly effective contraception in reducing maternal morbidity and mortality worldwide,” says Ralph, who conducted the research while at University of California Berkeley. More research needs to be done to quantify the risks and benefits of providing Depo, and these calculations also have to be adjusted for specific regions and even particular clinics. “One thing to consider is whether women have access to other contraceptive options, whether they will be willing to take up these contraceptive options, and ensuring that women will be comfortable with them,” she says. “I would love to see these findings applied to specific regions. I think that would help women make the most informed decisions.”