A study recently published in Lancet Infectious Diseases found that women with HIV-positive partners who used the injectable hormonal contraceptive DMPA were twice as likely to contract the virus than women who did not use DMPA. In addition, HIV-positive women using DMPA were twice as likely to pass the virus to their HIV-negative partners than women who did not use it. (Other hormonal contraceptives were also implicated in increased HIV transmission, but so few women in the study were using them that the sample size was not large enough to yield statistically significant findings.)

The theory is that the hormones have an immunological effect.  The difference between the DMPA and non-DMPA-using groups was not due to a difference in condom use; that was one of the variables the scientists controlled for in their analysis.

The researchers noted that contraceptive use was based on self-reporting, raising the possibility of recall bias. They recommend doing followup studies using randomized trials to confirm or disconfirm the findings. They also recommend that:

Women should be counselled about potentially increased risk of HIV-1 acquisition and transmission with hormonal contraception, especially injectable methods, and about the importance of dual protection with condoms to decrease HIV-1 risk. Non-hormonal or low-dose hormonal contraceptive methods should be considered for women with or at-risk for HIV-1.

The New York Times reports that the World Health Organization has scheduled a meeting for January to discuss whether the evidence is strong enough to warn women that DMPA may increase their risk of contracting HIV.

We advocate informing women that there may be a risk. However, we also acknowledge some complicating factors. Pregnancy itself can be dangerous for many women, particularly those in the developing world who may have already had many children and who lack access to modern health care. Pregnancy may even increase the possibility of HIV transmission. If women stop using effective contraception for fear of HIV transmission, they might end up less safe — particularly if this study is later disconfirmed by randomized trials.

What does all of this mean for family planning freedom? The position taken by All Our Lives is that women should have access to all safe family planning methods, and all relevant information about them based on the strongest available evidence, to be able to choose the appropriate methods for their own situations. Some methods are safe for some women and not for others; that's one reason that a wide range of methods needs to be available to every woman. Many women in the developing world use DMPA because it can be administered by personnel with little medical training and each injection lasts three months, meaning that it can be used in situations where women have little access to medical facilities. Better access to medical care would allow more women to choose from alternative methods that do not carry an increased risk of HIV transmission.