Impact of Vaginal Microbiota on Gestation and Labour

Abstract

Background. Imbalances of vagina microbiota in pregnant women entail the development of bacterial vaginosis and candidal vulvovaginitis. Lactobacterial strains modulate pro-inflammatory epithelium responses to enhance resistance, which renders lactobacteria promising agents in pregnant women with elevated pH.Objectives. Assessment of the lactobacterial impact on vaginal microbiota and the course of gestation and labour.Methods. A total of 261 pregnant women were examined and separated by cohorts according to pH of vaginal fluid: ≥4.5 in cohort 1 (n = 147), <4.5 in cohort 2 (n = 114). Cohort 1 had age 29.9 (4.6) years, cohort 2 — 29.0 (4.6) years, p = 0.55. Screening: at weeks 11–14, 18–21, 30–34 and 36–41 of gestation we performed vaginal pH-metry, cervicometry, determined opportunistic pathogens and lactobacteria with mass spectrometry. Cohort 1 received lactobacteria. Statistical analyses were performed with Statistica 10.Results. In cohort 1 receiving lactobacteria, the number of women devoid of opportunistic flora increased from 31.29 to 43.53%. In cohort 2 not receiving lactobacteria, this number decreased from 53.51 to 35.09%. In cohort 1, L. jensenii (correlates with bacterial vaginosis rate) was primarily isolated in 9.52% women, and in 14.91% — in cohort 2. The rate of L. jensenii increased to 14.96% in cohort 1 (receiving lactobacteria) and decreased to 3.51% in cohort 2 (not receiving lactobacteria). A higher L. jensenii rate correlated with absent growth of opportunistic pathogens. Increasing the rate of L. crispatus (suppresses opportunistic pathogens) to 14.96% in cohort 1 lead to a 1.9-fold diminishing of active opportunistic flora. An increase of L. crispatus from 7.02 to 30.7% in cohort 2 supressed active opportunistic growth 3.9-fold at a normal baseline pH. Cervicometry values were invariant between the cohorts. Pregnancy complications were not observed under abundant lactobacterial growth. The risk of gestation loss occurred in 1.4% of women in cohort 1 and in 10.5% — in cohort 2. Abnormal labour and premature rupture of foetal membranes were more frequent in cohort 2.Conclusion. With a less favourable premorbid condition in cohort 1, vaginal changes with background lactobacterial therapy facilitate gestational health in pregnancy. Many “sterile” niches, especially the maternal generative passages, represent active low biomass environments inhabited by unique typical maternal microflora. Most remarkable is the correlation between health of vaginal microbiota and abnormal labour.