Oral and injectable contraception use and risk of HIV acquisition among women in sub-Saharan Africa

Abstract

OBJECTIVE:: Evaluate the effect of oral and injectable hormonal contraception (HC) on the risk of HIV acquisition among women in South Africa and Zimbabwe. DESIGN:: Secondary data analysis of 4913 sexually active women aged 18-49 years followed for up to 24 months in the MIRA phase III effectiveness trial of the diaphragm and lubricant gel for HIV prevention. METHODS:: Participants were interviewed quarterly about contraception and sexual behavior and were tested for pregnancy, HIV, and other sexually transmitted infections. We used a Cox proportional hazards marginal structural model, weighted by the inverse probability of HC use, to compare the risk of HIV acquisition among non-pregnant women reporting use of combined oral contraceptive pills (COC), progestin-only pills (POP), and/or injectable HC to women not using these methods. RESULTS:: During the study, 283 participants seroconverted. Use of oral contraceptives (POP or COC) was not associated with HIV risk (adjusted hazard ratio (HRa) = 0.86, 95% confidence interval (CI): 0.32, 1.78). Injectable HC was associated with a small non-significant risk of HIV infection (HRa = 1.34, 95% CI: 0.75, 2.37). The effect of injectable HC was similar in the unweighted site-adjusted only (HRa = 1.32, 95% CI: 1.00, 1.74) and baseline factor adjusted models (HRa = 1.27, 95% CI: 0.94, 1.72). CONCLUSIONS:: In this study, oral contraceptives were not associated with HIV acquisition. There is substantial uncertainty in the effect of injectable HC on HIV risk. These findings underscore the importance of dual protection with condoms and the need for diverse contraceptive options for women at risk of HIV infection