Objective: As the HIV/AIDS epidemic continues to spread in Africa and Asia, use of the injectable contraceptive steroid DMPA is widespread and has been increasing. Since studies dating back to 1992 have suggested that DMPA may increase the transmission of HIV to women, we endeavored to determine if the extant epidemiological and biological evidence is sufficient to conclude that DMPA use constitutes a definite hazard to women's health.
Methods: We searched Medline using the search terms: contraceptives or contraception AND HIV and searched bibliographies of articles thus identified. We included in the meta-analysis all studies examining the association between use of DMPA (or injectable contraceptives comprising mostly DMPA) and the presence (cross-sectional studies, n = 8) or acquisition (longitudinal studies, n = 16) of HIV+ status in women, using a random effects models to estimate odds ratios (ORs; cross-sectional studies) and hazard ratios (HRs; longitudinal studies). Studies were excluded if the comparison group included women using any form of steroidal contraception.
Results: Statistically significant positive associations between DMPA use and HIV positivity were observed both in cross-sectional (OR = 1.41, 95% CI 1.15 - 1.73) and longitudinal studies (HR = 1.49, 95% CI 1.28 - 1.73). The biological plausibility of increased vulnerability to HIV infection due to progestational action (via thinning of the vaginal epithelial barrier and immunosuppression) as well as glucocorticoid agonistic immunosuppression, are discussed.
Conclusion: The epidemiological and biological evidence now make a compelling case that DMPA adds significantly to the risk of male-to-female HIV transmission.