Vaginal microbiota associated with preterm delivery

The aim of this study was to evaluate whether vaginal microbiota is associated with threatened premature labor and preterm delivery.

This prospective study enrolled 64 pregnant women who underwent vaginal microbiome analyses using 16S ribosomal RNA sequence method with informed consent. The 64 pregnant women consisted of 47 women with threatened premature labor and 17 women with other diseases (non-threatened premature labor) in a case-control study. In a cohort study of threatened premature labor group, 23 pregnancies ended in preterm delivery, and the remaining 24 ended in full-term deliveries. The differences in vaginal microbiota between threatened and non-threatened premature labor groups, and between preterm and full-term delivery groups were evaluated.

There were no differences in vaginal microbiota between threatened and non-threatened premature labor groups. There were significant differences between preterm and full-term delivery groups in Nugent score [median 3 (range 0-7) vs. 0 (0-4), p < 0.05], percentage of Lactobacillus species [88% (0-100) vs. 99.8% (55.4-100), p < 0.01], the number of bacterial species [3 (1-13) vs. 2 (1-5), p < 0.05], and positivity of Ureaplasma species (61% vs. 17%, p < 0.01). Univariate and multivariable analyses revealed that positivity of Ureaplasma species was a predictive factor of preterm delivery in women with threatened premature labor (OR, 6.5; 95% CI, 1.3-33.0; p < 0.05).

Increased positivity of Ureaplasma species in vaginal microbiota was a risk factor for preterm delivery among women with threatened premature labor. Vaginal microbiome analysis may identify high risk pregnancies for preterm delivery.