February 24, 2012
The authors undertook the current prospective cohort study to investigate the association between hormonal contraceptives and the risk of HIV-1 seroconversion and the prevalence of other STIs.
The study's subjects were 2,236 HIV-negative women who underwent screening in a biomedical intervention trial in Durban. Cox proportional hazards regression analysis was employed to model the association between the use of hormonal contraceptives and the risk of HIV-1 seroconversion. Logistic regression models were used to assess prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infections.
Among the women, the most common contraceptive methods were hormonal injectables (46.47 percent) and condoms (28.04 percent). "Overall, compared with women who reported using condoms or other methods as their preferred form of contraceptive, those who reported using hormonal contraceptives (injectables and oral pills) were less likely to use condoms in their last sexual act," the authors found. Use of hormonal injectables during the study period was significantly associated with increased risk for HIV-1 infection (adjusted hazard ratio, 1.72, 95 percent confidence interval 1.19-2.49, P=0.005). In addition, hormonal injectables were significantly associated with higher prevalent C. trachomatis infections (adjusted odds ratio 2.46, 95 percent CI 1.52-3.97, P<0.001).
"Hormonal injectables are highly effective and well tolerated family planning methods and have played an important role in reducing unplanned pregnancies and maternal and infant mortality," the authors concluded. "However, they do not protect against HIV-1 and other sexually transmitted infections. This study reinforces the importance of comprehensive contraceptive counseling to women about the importance of dual protection, such as male condoms and hormonal contraceptives use."