Vaginal Mycoplasmataceae colonization and association with immune mediators in pregnancy

To determine the prevalence of Mycoplasmataceae species in pregnant women and evaluate their association with immune system mediators.

Women were prospectively enrolled between 16-22 weeks' gestation. Vaginal swabs were self-collected and analyzed with PCR for Mycoplasma hominis (MH) and Mycoplasma genitalium (MG) as well as Ureaplasma urealyticum (UU) and Ureaplasma parvum (UP) (collectively, Myc). Immune mediators were measured via Luminex multiplex assay. Women with vaginal Mycoplasmataceae were compared to women without Myc, and women with Mycoplasma species (MH or MG) were compared to women without MH or MG. Linear regression models were used to investigate the relationship of the presence of Mycoplasmataceae on log-transformed immune mediators while controlling for confounders using propensity scores.

One-hundred-twenty women were enrolled and had complete lab data available. Colonization was 20.8, 2.5, 10.0, and 48.3% for MH, MG, UU, and UP, respectively. Women with any Mycoplasmataceae were more likely to be younger, of the Black race, and have public insurance. There were no significant differences in immune mediators between women with vaginal Mycoplasmataceae versus those without. After controlling for confounders, women with MH and/or MG had significantly elevated levels of IL-1β compared to women without MH or MG (estimate =  1.12; 95% CI =  0.33, 1.93). There were no other significant differences in immune mediators in women with MH and/or MG compared to those without.

Colonization rates were highest for UP and lowest for MG. Higher IL-1β levels were seen in the presence of MH and/or MG, indicating that these less frequently encountered organisms may incite a stronger host response. There were no other significant differences in immune mediator levels.