Background: The incidence of gestational diabetes mellitus (GDM) has increased in China in recent years. Evidence suggests that gut microbiota composition plays a role in the development of GDM. This study aimed to characterize the gut microbiota in pregnant women with GDM using high-throughput sequencing methods. Methods: A total of 60 pregnant women, comprising 30 diagnosed with GDM and 30 healthy controls, were enrolled at our hospital in this study, conducted from September 2021 to August 2022. Fecal samples were collected for DNA extraction, followed by amplification through polymerase chain reaction (PCR). High-throughput sequencing was then performed to analyze the 16S rDNA V3–V4 fragments in the fecal samples. Results: The diversity of the gut microbiota showed that the Ace, Chao, and Sobs indices were higher in the GDM group compared with those in the healthy control group (p < 0.05). The Shannon index was also significantly higher in the GDM group (p < 0.05). At the phylum level, the gut microbial communities in both groups predominantly comprised the following four phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidota. Compared with the healthy control group, the relative abundance of Firmicutes and Bacteroidota was significantly higher in the GDM group (p < 0.05), whereas Actinobacteria and Proteobacteria were significantly lower (p < 0.05). At the genus level, the profusion of Shigella, Romboutsia, Paraprevotella, unclassified Clostridium UCG-014, and Trichospira increased significantly in the GDM group (p < 0.05). Conclusions: During the third trimester, the intestinal microbial communities of diabetic pregnant women differ significantly from those of healthy pregnant women. In the intestinal flora of patients with GDM, the abundance of Firmicutes and Bacteroidota increased significantly, while that of Actinobacteria and Bifidobacterium decreased significantly. These findings suggest that the occurrence of GDM is accompanied by a reduction in the beneficial bacterium Bifidobacterium.
Zhao et al. (Mon,) studied this question.