Amniotic fluid and vaginal microbiota in pregnant women with gestational diabetes mellitus by metagenomics

Aims

To compared the amniotic fluid and vaginal microbiota of pregnant women, who developed gestational diabetes mellitus to those who did not, and explored if any differences exist in the composition and functional genes of their amniotic fluid and vaginal microbiota.

Methods

We compared the amniotic fluid and vaginal microbiota of five GDM patients and five non-GDM pregnant women in the third trimester of pregnancy by using metagenomics, and analyzed the characteristics, functions, and differences between two groups.

Results

The analysis of the amniotic fluid showed significant differences in genus and species. In contrast, there was no significant difference in vaginal microbial community structure between two groups. The alpha diversity in the GDM group was higher than the control, but the difference was not statistically significant. There was a statistically significant difference in the species-level beta-diversity measured by Bray–Curtis distance of the amniotic fluid communities between two groups, while no significant differences were observed in the vaginal microbiota. Regarding the functions, we observed that the microbial communities of the amniotic fluid and vaginal secretions were involved in the regulation of a variety of host metabolic pathways, including carbohydrate metabolism, membrane transport, energy, amino acid metabolism, nucleotide metabolism, etc. No significant differences were observed between two groups, but different sites exist.

Conclusion

The amniotic fluid of this study was discovered to have a heterogeneous, albeit small in number, community of microorganisms.Our research suggests that gestational diabetes has a very limited impact on the amniotic fluid and vaginal microbiome. The composition and the functions of the microbiota at different sites are different.