Trichomonas vaginalis in Pregnancy: Patterns and Predictors of Testing, Infection, and Treatment

To identify factors associated with testing for and diagnosis of trichomoniasis in pregnancy and to describe patterns of treatment and tests of reinfection or persistence.

We conducted a retrospective cohort study of women who delivered from July 2016 to June 2018 at one institution. Testing for Trichomonas vaginalis infection was done by wet mount microscopy or by nucleic acid amplification testing for routine prenatal testing or symptomatic visits. Poisson regression was used to identify factors associated with testing for trichomoniasis and testing positive in pregnancy. Treatment and re-testing patterns also were assessed.

Among 3,265 pregnant women, 2,489 (76%) were tested for T vaginalis infection. Of the total sample, 1,808 (55%) were tested by wet mount microscopy, 1,661 (51%) by nucleic acid amplification testing, and 980 (30%) by both modalities. The sensitivity for microscopy compared with nucleic acid amplification testing was 26%, with a specificity of 99%. Factors associated with increased likelihood of being tested included younger age (adjusted risk ratio [aRR] 0.99, 95% CI 0.99-1.00) and bacterial vaginosis (aRR 1.17, 95% CI 1.01-1.37). Prevalence of trichomoniasis was 15% among those tested by any modality (wet mount or nucleic acid amplification testing). Risk factors for trichomoniasis included younger age (aRR 0.97, P<.01), being of black race (aRR 2.62, P<.01), abnormal vaginal discharge (aRR 1.45, P<.01), and chlamydia during the current pregnancy (aRR 1.70, P<.01). Women diagnosed by microscopy had a shorter time to treatment compared with those diagnosed by nucleic acid amplification testing. Most (75%) women with positive infections had a test of reinfection; 29% of these were positive. Bacterial vaginosis was associated with decreased risk of a positive test of reinfection.

Although testing for and treatment of trichomoniasis during pregnancy is not routinely recommended, the high burden of infection among some pregnant women demonstrates a need to further understand patterns of T vaginalis testing and infection. Opportunities exist for improving timely treatment of trichomoniasis and test of reinfection.