A data review by the U.S. Centers for Disease Control and Prevention (CDC) has failed to confirm a previously described association between injectable or oral hormonal contraceptives and increased likelihood of HIV infection or disease progression, researchers reported in the June 22, 2012, issue of Morbidity and Mortality Weekly Report.
Some prior research has suggested that hormonal contraceptives — especially injectable methods such as depot medroxyprogesterone acetate (DMPA or Depo-Provera) that are widely used in Africa — are associated with an elevated risk of HIV acquisition; other studies have not seen such a link.
In February of this year the World Health Organization (WHO) affirmed its 2009 guidance that women living with or at risk for HIV should continue to use hormonal contraception, concluding that the overall body of evidence indicates that the benefits outweigh the potential risks.
The recent CDC review, which assessed evidence regarding the link between hormonal contraceptives and risk of HIV acquisition, transmission, and disease progression — came to a similar conclusion. A panel of researchers from within and outside the CDC looked at 3 systematic reviews conducted for WHO.
On the question of HIV acquisition among HIV negative women, 20 observational studies were identified, most of which found no significant association between oral contraceptive use and HIV infection. Among studies that assessed injectable methods including DMPA and norethisterone enanthate (NET-EN), evidence was mixed, and all studies had limitations and potential residual confounding.
Overall, they concluded, "the evidence does not suggest an association between oral contraceptive use and risk for HIV acquisition," adding that, "[e]vidence on injectable use does not establish a causal association with HIV acquisition, nor does it definitively rule out the possibility of an effect."
A single study looking at risk of female to male transmission from HIV positive women showed a significant increase in transmission risk with injectable but not oral contraceptives. But this study had some weakness and limited statistical power, leading the reviewers to conclude, "Given the limited direct data on this question, more evidence is needed."
Finally, 10 observational studies looked at the link between hormonal contraception among HIV positive women and risk of HIV disease progression including viral load, CD4 T-cell count, AIDS-defining illness, and/or death.
Although a single randomized controlled trial did show increased risk among women using hormonal contraceptives, the reviewers concluded that, overall, "this evidence is reassuring and does not suggest an increased risk for HIV disease progression with hormonal contraceptive use."
The reviewers also considered how the global WHO recommendations might apply to the U.S. While acknowledging differences such as lower HIV incidence and prevalence, greater access to healthcare, wider use of antiretroviral therapy, and lower risk of pregnancy complications, they still favored adopting the revised WHO recommendations.
Thus, the data review affirms the previous CDC guidance set forth in "U.S. Medical Eligibility Criteria for Contraceptive Use, 2010," which provided the following evidence-based guidance for contraceptive use for women with specific conditions including having or being at risk for acquiring HIV:
1. Use of hormonal contraceptives, including combined hormonal contraceptives, progestin-only pills, DMPA, and implants, is safe for women at high risk for HIV infection or infected with HIV.
2. All women who use contraceptive methods other than condoms should be counseled regarding the use of condoms and the risk for sexually transmitted infections.
The updated guidelines added a clarification that evidence regarding progestin-only injectable contraceptives remains inconclusive, and they also noted the need for further research on an expanded mix of contraceptive methods. The CDC also added a clarification regarding potential interactions between hormonal contraceptives and antiretroviral drugs, given that the latest DHHS guidelines recommend that all people diagnosed with HIV should be offered treatment.
"Contraception is critically important to prevent unintended pregnancy among women at risk for HIV infection or infected with HIV and such women can continue to use all hormonal contraceptive methods without restriction," the reviewers concluded. "However, HIV infection preventive measures, such as voluntary testing and counseling, access and adherence to [antiretroviral] drugs, and correct and consistent use of condoms, should be strongly encouraged among all women at risk for HIV acquisition and women living with HIV infection."