Women's multisite microbial modulation during pregnancy.

The composition of female microbiome varies with age, physiological and socio-behavior conditions. Also, changes in microbiome composition are observed as pregnancy progresses, especially in the vaginal site. Together with the physiological adaptations of gestation, changes in microbiome composition seem to be fundamental for proper fetal development. This study aimed at simultaneously evaluating the vaginal, gut, and oral microbiome of healthy pregnant women, and comparing it with those observed in healthy non-pregnant women of reproductive age. In a cross-sectional study, vaginal, oral and gut samples were collected from 42 pregnant and 18 non-pregnant women, and the microbiome composition was evaluated by 16S rRNA sequencing, using Illumina platform. In the pregnant group, we observed a positive correlation between Eubacterium and Akkermansia in the gut samples; between Eubacterium and Ruminococcus in the vaginal samples; and between Streptococcus and Gemella in the oral samples. Notwithstanding, we observed a negative correlation between Lactobacillus and Atopobium and between Lactobacillus and Gardnerella in vaginal microbiome. Prevotella was the only genus found in all three sites studied; however, there was no signal of bacterial influence between sites during pregnancy. These results suggest that in addition to hormonal and immunological variations during healthy pregnancy, the female body also undergoes microbiome modulation in multiple sites in order to maintain an eubiotic status.

Microbiome and its relation to gestational diabetes.

PURPOSE: Gestational diabetes mellitus (GDM), the major endocrine pathology in pregnancy, has been associated with the development of an intense inflammatory process and increased insulin resistance. The maternal microbiota is involved in several metabolic functions; however, its role in GDM physiopathology remains unclear. The aim of this study was to assess the composition of the microbiota at different sites and evaluate its relationship with the occurrence of GDM. METHODS: This cross-sectional study recruited women in the third trimester of gestation with and without GDM. Oral, vaginal, and stool samples were evaluated using next-generation sequencing. We included 68 participants: 26 with and 42 without GDM. RESULTS: The analysis of the oral microbiome did not show significant differences in phyla and genus among the studied groups. In contrast, GDM patients presented a specific vaginal and intestinal microbiome composition, which was less diverse than those found in the control group, showing genera related to dysbiosis. CONCLUSIONS: Our findings suggest that changes in the composition of the vaginal and intestinal microbiome might be involved in the development of GDM. The follow-up of these patients in order to evaluate vaginal and intestinal samples after delivery may contribute to understanding the development of metabolic disease in women with previous GDM.