Dynamics of the species composition of vaginal microorganisms in women before delivery and at different times of the postpartum period

Background: Vaginal microbiota is a factor that determines a woman’s health. Infectious complications of pregnant women, women in labor and newborns are often associated with a significant change in its composition. Analysis of the species diversity of vaginal microbiota during pregnancy and the postpartum period primarily contributes to the study of physiological processes and the concept of a “healthy” vaginal environment during these significant periods of a woman’s life.

Aim: The aim of this study was to evaluate the dynamic change in the species composition of vaginal microorganisms before delivery and at different times of the postpartum period in women with natural labor.

Materials and methods: This study involved 24 pregnant women who delivered vaginally. Each patient was examined at three time points: 37–40 weeks of pregnancy (visit 1), 4–5 days of the postpartum period (visit 2), and 6–8 weeks after delivery (visit 3). The species composition of the vaginal microbiota was studied using a comprehensive test based on real-time quantitative polymerase chain reaction.

Results: We found a decrease in the total bacterial mass in the vaginal biotope of women in labor after 4–5 days of the postpartum period and 6–8 weeks after delivery in comparison with the examination before delivery (p < 0.0005). Similar changes were noted in the composition of the lactobacillary microbiota: the concentration of lactobacilli decreased in the postpartum period in comparison with that before delivery (p < 0.05). Compared to the examination before delivery, 6–8 weeks after delivery in women, we observed a decrease in the frequency of Lactobacillus crispatus dominance (p < 0.05), while the frequency of Lactobacillus iners dominance in the postpartum period increased (p < 0.05). Among the representatives of the opportunistic vaginal microflora, the most frequently prevalent species were Gardnerella vaginalis, Prevotella bivia, Porphyromonas spp., Fannyhessea vaginae, Staphylococcus spp., Streptococcus spp., and Ureaplasma spp. In all women with severe vaginal microbiota disruption before delivery, an ascending bacterial infection was established according to the histological examination of the placenta after delivery (p < 0.05).

Conclusions: In most cases, the observed changes in the qualitative and quantitative composition of the vaginal microbiota in pregnant women and women in labor are physiological. At the same time, a consistent study of the vaginal microbiota during pregnancy and at different times of the postpartum period will allow for identifying possible risk factors for the development of infectious diseases in the mother and newborn and expand the possibilities for timely diagnosis and treatment of the identified disorders.