Trichomonas vaginalis and Spontaneous Preterm Birth in a High-Risk Obstetric Cohort in Atlanta, GA

Trichomonas vaginalis (TV) is the most prevalent nonviral sexually transmitted infection globally, but routine screening is not recommended in HIV-negative individuals. There is a significant racial/ethnic health disparity in TV infection rates. Evidence regarding the association between TV and adverse perinatal outcomes is conflicting, but a recent large meta-analysis found a modest increased risk of preterm birth with TV infection (odds ratio, 1.27; 95% confidence interval, 1.08-1.50). The current study was undertaken to evaluate whether TV infection increases the risk of spontaneous preterm birth (sPTB) in a high-risk obstetric cohort in Atlanta, GA.

We conducted a retrospective cohort study of women delivering at a safety-net hospital in Atlanta between July 2016 and June 2018. Women delivering a singleton live fetus at >20 weeks' gestation were included. The diagnosis of TV was by nucleic acid amplification testing. The outcome of interest was sPTB before 37 weeks' gestation. Multivariable Cox proportional hazards modeling was used to estimate the effect of TV on sPTB, controlling for confounding variables, including clinical and demographic characteristics. Several sensitivity analyses were undertaken.

There were 3723 deliveries during the study period, and approximately half (46%) were screened for TV with nucleic acid amplification testing. After exclusions, the analytic cohort included 1629 women. Median age was 26 years (interquartile range, 22-31 years), and 70% of participants were listed as non-Hispanic Black in the electronic medical record. The prevalence of TV was 16% (n = 257). The sPTB rate was 7% (n = 112). In multivariable Cox proportional hazards modeling, TV infection was not associated with a statistically significantly increased risk of sPTB (hazard ratio, 1.34; 95% confidence interval, 0.84-2.13; P = 0.22). Factors associated with sPTB included history of PTB, adequate plus or transfer of prenatal care (vs. adequate/intermediate prenatal care utilization using the Kotelchuck index), recreational substance use, and Chlamydia trachomatis diagnosed during the current pregnancy. Results were not substantively different in sensitivity analyses.

The prevalence of TV was high in this cohort. Its infection was not associated with a statistically significantly increased risk of sPTB. Nevertheless, the magnitude of effect is consistent with prior meta-analyses.