Objectives: The study attempted to determine the incidence of HIV among pregnant women in Kabarole District, Uganda, and to identify socio-demographic and behavioral risk factors for seroconversion during pregnancy.
Methods: We carried out a retrospective cohort study among women for whom a documented HIV-negative test result from the first pregnancy trimester could be confirmed using available records, and who were HIV-retested in the third trimester or during delivery. In total, 1610 pregnant women from three different healthcare settings took part in the study. We captured the results of repeated HIV tests and conducted semi-structured interviews to explore participants' socio-demographic characteristics and sexual risk behavior. For HIV incidence rates, we calculated the number of seroconversions per 100 person-years. We used Fisher's exact test to test for potential associations. Penalized maximum likelihood logistic regression and Poisson regression were applied to adjust for potential confounders.
Results: The overall HIV incidence rate among participants was 2.9/100 women-years. Among socio-demographic characteristics, the multivariable analysis showed a significant association of marital status with HIV incidence in pregnancy (IRR 8.78, 95%CI [1.13-68.33]). Risky sexual behaviors including higher number of sexual partners in pregnancy (IRR 2.78 [1.30-5.94]), unprotected sex with unknown persons (IRR 14.25 [4.52-44.93]), alcohol abuse (IRR 12.08 [4.18-34.90]) and sex under the influence of drugs or alcohol (IRR 6.33 [1.36-29.49]) were significantly associated with seroconversion in pregnancy (similar results in logistic regression).
Conclusions: HIV incidence was three times higher among our pregnant study population compared to the general female population in Uganda. This underlines the importance of HIV prevention and repeat testing during pregnancy. Identified risk groups should be considered for pre-exposure prophylaxis.