Hormonal contraception and risk of sexually transmitted disease acquisition: Results from a prospective study

OBJECTIVES: To examine the relationship between use of oral contraceptive p ills or depot medroxyprogesterone acetate and sexually transmitted disease acquisition. STUDY DESIGN: Prospective cohort included 948 Kenyan prostitutes, Multivari ate Andersen-Gill proportional hazards models were constructed, adjusting f or sexual behavioral and demographic variables. RESULTS: When compared with women who were using no contraception, users of oral contraceptive pills were at increased risk for acquisition of chlamyd ia (hazard ratio, 1.8; 95% confidence interval, 1.1-2.9) and vaginal candid iasis (hazard ratio, 1.5; 95% confidence interval, 1.2-1.9) and at decrease d risk for bacterial vaginosis (hazard ratio, 0.8; 95% confidence interval, 0.7-1.0). Women using depot medroxyprogesterone acetate had significantly increased risk of chlamydia infection (hazard ratio, 1.6; 95% confidence in terval, 1.1-2.4) and significantly decreased risk of bacterial vaginosis (h azard ratio, 0.7; 95% confidence interval, 0.5-0.8), trichomoniasis (hazard ratio, 0.6; 95% confidence interval, 0.4-1.0), and pelvic inflammatory dis ease (hazard ratio, 0.4; 95% confidence interval, 0.2-0.7). Consistent cond om use was associated with significantly decreased risk of gonorrhea, chlam ydia, genital ulcer disease, bacterial vaginosis, and pelvic inflammatory d isease. CONCLUSIONS: The use of oral or injectable hormonal contraception altered s usceptibility to sexually transmitted diseases, which may in turn influence transmission of human immunodeficiency virus type 1. Consistent condom use was protective with regards to sexually transmitted disease and should be encouraged for the prevention of sexually transmitted disease and human imm unodeficiency virus type 1 among women who use hormonal contraception.