Combined oral contraceptives (COC) and depot-medroxyprogesterone acetate (DMPA) are among the most widely used family planning methods; their effect on HIV acquisition is not known.
To evaluate the effect of COC and DMPA on HIV acquisition and any modifying effects of other sexually transmitted infections.
This multicenter prospective cohort study enroled 6109 HIV-uninfected women, aged 18–35 years, from family planning clinics in Uganda, Zimbabwe and Thailand. Participants received HIV testing quarterly for 15–24 months. The risk of HIV acquisition with different contraceptive methods was assessed (excluding Thailand, where there were few HIV cases).
HIV infection occurred in 213 African participants (2.8/100 woman-years). Use of neither COC [hazard ratio (HR), 0.99; 95% confidence interval (CI), 0.69–1.42] nor DMPA (HR, 1.25; 95% CI, 0.89–1.78) was associated with risk of HIV acquisition overall, including among participants with cervical or vaginal infections. While absolute risk of HIV acquisition was higher among participants who were seropositive for herpes simplex virus 2 (HSV-2) than in those seronegative at enrolment, among the HSV-2-seronegative participants, both COC (HR, 2.85; 95% CI, 1.39–5.82) and DMPA (HR, 3.97; 95% CI, 1.98–8.00) users had an increased risk of HIV acquisition compared with the non-hormonal group.
No association was found between hormonal contraceptive use and HIV acquisition overall. This is reassuring for women needing effective contraception in settings of high HIV prevalence. However, hormonal contraceptive users who were HSV-2 seronegative had an increased risk of HIV acquisition. Additional research is needed to confirm and explain this finding.
From the aClinical Research Department, Family Health International, Research Triangle Park, North Carolina, USA
bDepartment of Biostatistics, University of Washington and the Statistical Center for HIV/AIDS Research & Prevention (SCHARP), Fred Hutchinson Cancer Research Center and the
cStatistical Analysis Unit, Cystic Fibrosis Therapeutics Development Network, Children's Hospital and Regional Medical Center, Seattle, Washington, USA
dFaculty of Medicine, Makerere University, Kampala, Uganda
eDepartment of Obstetrics and Gynecology, University of Zimbabwe, Harare, Zimbabwe
fDepartment of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
gNational Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA
hDepartment of Obstetrics, Gynecology and Reproductive Sciences, University of California at San Francisco, San Francisco, California, USA
iResearch Institute for Health Sciences (RIHES), Chiang Mai University, Chiang Mai, Thailand
jDepartment of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
*See the Appendix for members of the study group.
Received 22 March, 2006
Accepted 24 August, 2006
Correspondence to Dr C.S. Morrison, Family Health International, PO Box 13950, Research Triangle Park, NC 27709, USA. E-mail: firstname.lastname@example.org