New Study Finds Link Between Depo-Provera Birth Control and HIV Risk

But should you opt for a different form of birth control? Not so fast. (Photo: Getty Images)

With so many methods of contraception on the market, it can be tough to decide which works best for specific populations, and what risks might be associated with each one. Research over the past three decades has looked into how hormonal contraceptives might affect HIV risk in women.

A new, large meta-analysis of 12 different studies in sub-Saharan Africa from the University of California, Berkeley, may provide insight into how popular forms of hormonal contraception (HC) may impact HIV transmission.

The scientists selected the 12 studies, which included more than 39,500 women, based on strict criteria — like making sure to isolate and account for confounding factors, such as condom use, which might affect HIV transmission.

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According to the research published in The Lancet of Infectious Diseases, women who used the injectable birth control depot medroxyprogesterone acetate (more commonly known as Depo-Provera) saw a moderately increased risk of becoming infected with HIV. Depo-Provera is generally injected every three months to help prevent pregnancy. The scientists also looked at HIV risk relative to other methods of hormonal contraception, including injectable norethisterone oenanthate (also known as NET-OEN), combined oral contraceptives and progestin-only pills.

Only the Depo-Provera seemed to increase the risk of contracting HIV, by roughly 40 percent compared to women using non-hormonal birth control or no birth control at all. The researchers found the risk was a bit lower among studies conducted within the general population — meaning women without additional risk factors like an HIV-positive partner, for instance — seeing about a 31-percent increased risk.

Since the research didn’t examine cause, lead study author Lauren Ralph, Ph.D, an epidemiologist at University of California, Berkeley, says it’s unclear why Depo-Provera seemed to up the risk of HIV infection.

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Prior research has struggled to provide clear global guidance on birth control for women, says Ralph. “While some studies have found an association between use of hormonal contraception, primarily injectable forms like Depo and other progestin-based methods, others have found no association,” she tells Yahoo Health. “Our goal was to systematically review the available evidence and, when appropriate, combine the results of previous studies to produce an overall pooled estimate of risk for each type of hormonal contraception — Depo-Provera, NET-OEN, and oral contraceptive pills.”

A side notes, in case you’re wondering. Why do scientists focus primarily on the sub-Saharan populations? It has to do with HIV prevalence and the variance in populations’ HC methods, says Ralph, which makes data easier to come by and analyze.

For instance, Depo-Provera is more commonly used among women in African populations than among women in the United States. “In many settings including the U.S., HIV infection is rarer compared to other common sexually transmitted infections,” says Ralph. “However, within each specific population, some groups are affected more than others. This is the case in our study, where we found that Depo users were 40 percent more likely to be infected than nonusers.” Though the risk of HIV in both groups remains low, Ralph stresses.

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She also explains that the results of her study do not indicate Depo-Provera should be pulled from use. “This increased risk of HIV associated with Depo needs to be balanced against the known benefits of highly effective contraception,” she explains. “For example, you have to look at injectable hormonal contraceptives’ role in preventing unintended pregnancy and its associated morbidity and mortality. Current modeling studies suggest that withdrawal of Depo would not be warranted in most countries for women in the general population.”

So, basically: If you’re on Depo-Provera, don’t panic. “There are many factors that women and their health care providers must consider when deciding on a birth control method,” says Ralph. Ask your physician if you have questions about what contraceptive is best for you individually, but bottom line? Every case is different, especially in places like the United States.

Globally, though, this is a bigger debate — especially among populations where HIV risk is generally higher. Finding the most effective birth control method to protect a woman’s overall health is always (and should continue to be) a topic of conversation.

“Use of these modern contraceptive methods offers women effective and discreet protection from unintended pregnancy, resulting in significant reductions in maternal and infant morbidity and mortality, and enabling women to achieve other life goals,” says Ralph. “But now having a single pooled estimate by method might help streamline the debate about whether use of hormonal contraception increases women’s risk of acquiring HIV, which is of critical importance.”

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