Why this study is unique.

A possible relationship between hormonal contraceptive use and HIV acquisition has been investigated in approximately 30 studies. However, understanding of this possible relationship has remained poor. Study results have been inconsistent, in part because nearly all these studies have been designed to investigate other research questions and have had important methodological shortcomings. Only 12 prospective studies--the design of which reduces some sources of bias to results--have examined hormonal contraceptive use and HIV infection. Only six of those studies have considered a possible relationship between the use of the injectable hormonal contraceptive depot-medroxyprogesterone acetate (DMPA) and HIV infection.

The present study, (1) funded by the U.S. National Institute of Child Health and Human Development and conducted by FHI researchers and collaborating institutions, is unique and standard-setting in that it is:

* The only large prospective cohort study designed specifically to evaluate the relationship between the use of low-dose COCs or DMPA and HIV acquisition. Conducted in Uganda, Zimbabwe, and Thailand, this study involved some 6,100 HIV-negative, 18- to 35-year-old women in three exposure groups of roughly equal size: combined oral contraceptive (COC) users, DMPA users, and women not using hormonal contraception. With this number of study participants, the power of the study to detect a potential association was high. Notably, the study's prospective cohort design allowed women to continue using their voluntarily chosen contraceptive method.

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* Conducted among family planning clients, who are considered to be at ...