How does hormonal contraception affect HIV therapy?
Until recently, no research had addressed these concerns. But one study, conducted among 154 HIV-infected women participating in the largest prospective study of the impact of HIV infection on U.S. women, found that hormonal contraceptive use did not reduce the effectiveness of the combinations of three or more different ARV drugs known as highly active antiretroviral therapy (HAART). (1)
Researchers compared the effects of HAART among 77 hormonal contraceptive users and 77 non-users participating in the Women's Interagency HIV Study (WIHS). Members of the two groups were matched for age, ethnicity, and pretreatment measures of HIV disease progression (the number of CD4+ immune system cells per cubic millimeter of blood and the level of HIV in the blood).
The analysis revealed no statistically significant differences in immunologic or virologic responses to therapy between women who had been using hormonal contraceptives when they began HAART and non-users. Similar percentages of women in both groups experienced increases in CD4+ cell counts and decreases in viral load to undetectable levels. Moreover, the duration of hormonal contraceptive use before HAART initiation did not affect these positive responses to the therapy.
"The relatively low use of hormonal contraception among WIHS participants limited the statistical power of our study, and therefore our ability to detect very small effects on treatment response," cautions Dr. Stephen Gange, an author of the study, WIHS principal investigator, and associate professor of epidemiology at Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA. "We also need additional data to assess whether long-term exposure to hormonal contraceptives influences the effectiveness of ARV therapy."
(1) Chu J, Gange SJ, Anastos K, et al. Hormonal contraceptive use and the effectiveness of highly active antiretroviral therapy. Am J Epidemiol 2005;161(9):881-90.