Relationship between gestational diabetes mellitus and anxiety symptoms and gut microbiome composition in pregnant women

Gestational diabetes mellitus (GDM) is a common metabolic complication of pregnancy associated with poor outcomes for both mother and baby. An expanding body of research highlights the gut microbiota’s influence on host metabolism and neurobehavioral processes, yet how gestational diabetes mellitus, anxiety symptoms, and microbial communities interact is still unclear. To address this gap, we profiled gut-microbiome changes in pregnant women presenting with both GDM and clinically significant anxiety. A total of 120 participants were categorized into four groups: GDM with anxiety (G + A), GDM without anxiety (G + NAF), non-GDM with anxiety (NG + A), and non-GDM without anxiety (NG + NA). Stool specimens were obtained and subjected to 16S rRNA gene profiling of the V3–V4 hypervariable region using Illumina MiSeq sequencing. Results showed significant differences in fasting blood glucose between GDM and non-GDM groups. GDM groups exhibited enrichment of Enterobacteriaceae and reduction of Faecalibacterium, while anxiety groups showed increased Lactococcus and Streptococcus. The dual-exposure group (G + A) demonstrated unique enrichment of oral-derived genera (e.g., Fusobacterium and Actinomyces). Among 963 OTUs identified, 681 were core OTUs shared across groups. GDM and anxiety groups possessed 42 and 32 unique OTUs, respectively, with 26 OTUs specific to the G + A group. LEfSe analysis revealed 16 phylogenetically conserved taxa distinguishing GDM and non-GDM groups, while anxiety-positive groups were characterized by Bacilli and Negativicutes. These findings suggest that GDM and anxiety are associated with distinct gut microbiota profiles, highlighting potential microbial biomarkers for early diagnosis and intervention.