Chlamydia, Gonorrhea, and Incident HIV Infection During Pregnancy Predict Preterm Birth Despite Treatment

Background. Identifying predictors of preterm birth (PTB) in high-burden regions is important as PTB is the leading cause of global child mortality. Methods. This analysis was nested in a longitudinal study of human immunodeficiency virus (HIV) incidence in Kenya. HIV-seronegative women enrolled in pregnancy had nucleic acid amplification tests (chlamydia and gonorrhea), rapid plasma reagin (syphilis), wet mount microscopy (Trichomonas and yeast), and Gram stain (bacterial vaginosis); sexually transmitted infection (STI) treatment was provided. PTB predictors were determined using log-binomial regression. Results. Among 1244 mothers of liveborn infants, median gestational age at enrollment was 26 weeks (IQR, 22-31), and at delivery was 39.1 weeks (IQR, 37.1-40.9). PTB occurred in 302 women (24.3%). Chlamydia was associated with a 1.59-fold (P = .006), gonorrhea a 1.62-fold (P = .04), and incident HIV a 2.08-fold (P = .02) increased PTB prevalence. Vaginal discharge and cervical inflammation were associated with PTB, as were age <= 21 (prevalence ratio [PR] = 1.39, P = .001) and any STI (PR = 1.47, P = .001). Associations with chlamydia and incident HIV remained in multivariable models. Conclusions. STIs and incident HIV in pregnancy predicted PTB despite treatment, suggesting the need for earlier treatment and interventions to decrease genital inflammation.