Use of hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort study

Background Hormonal contraceptives are used widely but their effects on HIV-1 risk are unclear. We aimed to assess the association between hormonal contraceptive use and risk of HIV-1 acquisition by women and HIV-1 transmission from HIV-1-infected women to their male partners. Methods In this prospective study, we followed up 3790 heterosexual HIV-1-serodiscordant couples participating in two longitudinal studies of HIV-1 incidence in seven African countries. Among injectable and oral hormonal contraceptive users and non-users, we compared rates of HIV-1 acquisition by women and HIV-1 transmission from women to men. The primary outcome measure was HIV-1 seroconversion. We used Cox proportional hazards regression and marginal structural modelling to assess the effect of contraceptive use on HIV-1 risk. Findings Among 1314 couples in which the HIV-1-seronegative partner was female (median follow-up 18.0 [IQR 12.6-24.2] months), rates of HIV-1 acquisition were 6.61 per 100 person-years in women who used hormonal contraception and 3.78 per 100 person-years in those who did not (adjusted hazard ratio 1.98,95% CI 1.06-3.68, p=0.03). Among 2476 couples in which the HIV-1-seronegative partner was male (median follow-up 18.7 [IQR 12.8-24.2] months), rates of HIV-1 transmission from women to men were 2-61 per 100 person-years in couples in which women used hormonal contraception and 1.51 per 100 person-years in couples in which women did not use hormonal contraception (adjusted hazard ratio 1-97,95% CI 1.12-3.45, p=0.02). Marginal structural model analyses generated much the same results to the Cox proportional hazards regression. Interpretation 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.