Background: We investigated whether bacterial vaginosis is associated with HIV infection in pregnant women in North Carolina, U.S.A.
Methods: At 24 to 29 weeks' gestation, we recruited 724 women receiving prenatal care to provide interview information and vaginal swabs for Gram's stain scoring of vaginal flora.
Findings: As vaginal flora score increased, prevalence of HIV increased (trend p = .03). HIV prevalence was 0.8% (4 of 489 patients), 1.2% (1 of 84 patients), and 3.3% (5 of 151 patients) among women with normal, intermediate, and abnormal vaginal flora, respectively. All HIV-infected women were free from AIDS and were taking antiretroviral medication. Compared with women with normal vaginal flora, the relative risk for prevalence of HIV infection with intermediate flora was 1.5 (95% confidence interval [CI], 0.2, 12.9) and with abnormal flora was 4.0 (95% CI, 1.1, 14.9). The association between abnormal vaginal flora and HIV infection could not be explained by age, ethnicity, number of sexual partners in the past 6 months, sexually transmitted diseases (STDs), or douching during pregnancy.
Interpretation: In a population with a relatively low HIV prevalence, vaginal flora abnormalities were associated with prevalent HIV infection. We cannot determine whether vaginal flora abnormalities increase women's susceptibility to HIV infection or become more common after infection. The increased prevalence of bacterial vaginosis among HIV-infected pregnant women increases risk for preterm delivery. Incidence studies are required to discern whether control of bacterial vaginosis might reduce HIV infectivity.