The impact of maternal gestational diabetes mellitus on the microbiome of offspring: A systematic review.

Gestational diabetes mellitus (GDM) adversely affects maternal and offspring health, and the early-life microbiome is implicated in developmental programming. This systematic review quantitatively evaluated the association between maternal GDM and alterations in the gut and oral microbiomes of offspring. We systematically searched PubMed, Web of Science, and Embase (up to August 2025) for eligible studies adopting high-throughput sequencing techniques. Random-effects meta-analysis was performed for alpha diversity metrics, while findings on beta diversity and microbial taxonomy were summarized narratively. Twenty-one studies were included. The meta-analysis revealed no statistically significant differences in gut microbial alpha diversity between infants exposed to maternal GDM and unexposed controls. Beta diversity exhibited substantial inter‑study heterogeneity, with no consistent shifts observed. In infants born to mothers with GDM, several microbial taxa including Gammaproteobacteria, Enterobacteriaceae, Micrococcaceae, Propionibacteriaceae, Rikenellaceae, Megasphaera, Staphylococcus, Collinsella, Rothia, Pelomonas, Veillonella, Shewanellaceae and Prevotella tended to decrease in abundance, whereas Escherichia tended to increase. Notably, no microbial taxon presented consistent abundance changes in three or more studies, and these repeated findings were based on limited evidence. Delivery mode appeared to have minimal influence on offspring gut alpha diversity. Collectively, maternal GDM may not be strongly linked to shifts in offspring gut or oral microbial alpha diversity. However, the consistent dysregulation of specific microbial taxa in GDM-exposed offspring may exert potential impacts on offspring immune and metabolic development. Further longitudinal multicenter investigations are warranted to elucidate the causal relationships and long-term health implications of GDM-induced microbial alterations in children.