Nevirapine-based antiretroviral therapy does not reduce oral contraceptive effectiveness

Abstract

To evaluate the effect of nevirapine-containing antiretroviral therapy (ART) on combined oral contraceptive (COC) effectiveness. Nonrandomized prospective clinical trial. We enrolled HIV-infected women aged 18-35 years in South Africa and Uganda who had regular menses, were sexually active, and had no medical contraindications to COC use. We enrolled 196 women taking nevirapine-containing ART and 206 women not yet eligible for ART as a control group. We treated all participants with low-dose COCs. Our main outcomes were ovulation and pregnancy rates. We estimated ovulation in the first two cycles using weekly serum progesterone and tested for pregnancy monthly for 24 weeks. The median age of participants was 29 and their median CD4 cell count was 486. In the ART group, 43 of 168 (26%) ovulated in cycle 1, 30 of 163 (18%) in cycle 2, and 18 of 163 (11%) in both cycles. In the non-ART group, 26 of 168 (16%) ovulated in cycle 1, 31 of 165 (19%) in cycle 2, and 20 of 165 (12%) in both cycles. We found no significant difference in ovulation rates between groups: unadjusted odds ratio 1.36 (95% confidence interval 0.85-2.18). Pregnancy rates also did not differ: 10.0 per 100-women-years in the ART group and 10.1 per 100-women-years in the non-ART group. Self-reported COC adherence, condom use, vaginal bleeding, and adverse events were similar. Five serious adverse events were reported, all in the non-ART group. ART use did not affect risk of ovulation or pregnancy in women taking COCs, suggesting that nevirapine-containing ART does not interfere with COC contraceptive effectiveness.