Hormonal contraceptive use and female-to-male HIV transmission: a systematic review of the epidemiologic evidence.

OBJECTIVE To systematically review epidemiologic evidence assessing whether hormonal contraception alters the risk of HIV transmission from an HIV-positive woman to an HIV-negative male partner. DESIGN Systematic review. METHODS We included articles published or in press through December 15, 2011. We assessed studies with direct evidence on hormonal contraception use and HIV transmission, and summarized studies with indirect evidence related to genital or plasma viral load. RESULTS : One study provided direct evidence on oral contraceptive pills (OCPs) or injectable contraception and female-to-male HIV transmission; both injectables [Cox-adjusted hazard ratio (adjHR) 1.95, 95% confidence interval (CI) 1.06-3.58; marginal structural model (MSM) adjusted odds ratio (adjOR) 3.01, 95% CI 1.47-6.16] and OCPs (Cox adjHR 2.09, 95% CI 0.75-5.84; MSM adjOR 2.35, 95% CI 0.79-6.95) generated elevated point estimates, but only estimates for injectables were significant. Findings from 11 indirect studies assessing various hormonal contraception methods and viral genital shedding or setpoint were mixed, and seven of eight studies indicated no adverse effect of various hormonal contraception methods on plasma viral load. CONCLUSION The only direct study on OCPs or injectable contraception and female-to-male HIV transmission suggests increased risk with the use of injectables. Given the potential for confounding in observational data, the paucity of direct evidence on this subject, and mixed indirect evidence, additional evidence is needed.