Vaginal and amniotic fluid microbiota in women with preterm labor ‒ a comparative microbiological studY

Introduction and aim. This observational comparative study characterized the vaginal and amniotic fluids of women in preterm labor relative to those who delivered at term. A distinctive feature of this work is the paired, quantitative and culture-based assessment of both the vaginal and the amniotic fluid microbiota, while most previous studies have examined the vaginal compartment alone. Material and methods. Carried out at a single tertiary center, the study enrolled 120 women in preterm labor at 33–35 weeks of gestation together with 89 women delivering at term (≥38 weeks). Culture-based identification and quantitative analysis were applied to paired vaginal and amniotic fluid specimens. Results. Preterm labor was accompanied by a reduced prevalence of Lactobacillus spp. and by a markedly higher recovery of Gardnerella vaginalis (60.8%; odds ratio [OR] 12.27, 95% confidence interval [CI] 5.78–26.06) and Ureaplasma spp. (45.8%; OR 9.91, 95% CI 4.23–23.22), exceeding the term group (p<0.001). Higher vaginal pH and polymicrobial associations occurred more often. The amniotic fluid produced microbial growth in 53.3% of preterm cases and vaginal and amniotic detection of Ureaplasma spp. (φ=0.61; p<0.001). Conclusion. Vaginal dysbiosis showed an association with preterm labor that may be compatible with a contribution from ascending microbial colonization, though causality cannot be inferred from the present data.