Impact of Maternal GWG on Gut Microbiota Colonization in Neonates with GDM

Background: Maternal prenatal risk factors play a critical role in shaping the initial colonization of the gut microbiota in newborns. Objective: This study aimed to investigate the characteristics of the gut microbiota structure in neonates delivered by mothers with gestational diabetes mellitus (GDM) under different gestational weight gain (GWG) statuses and to analyze its potential associations with clinical indicators. Methods: A total of 89 neonates born to GDM mothers were enrolled in this study and categorized into three groups based on their mothers' GWG: adequate GWG (aGWG, n=39), inadequate GWG (iGWG, n=18), and excessive GWG (eGWG, n=32). The first meconium was collected from each neonate, and the gut microbiota structure was analyzed by 16S rRNA gene sequencing targeting the V3-V4 hypervariable regions. Results: The aGWG group was characterized by the predominance of Bosea ASV_1, whereas Pseudescherichia ASV_2 was more enriched in both the iGWG and eGWG groups. However, no significant overall differences in beta diversity were observed among the three GWG groups (ANOSIM R = 0.0145, p = 0.267; PERMANOVA p = 0.222). Furthermore, three community state types (CSTs) were identified based on the Dirichlet Multinomial Mixtures model: CST1 was dominated by Bosea ASV_1, CST2 had Parabacteroides merdae ASV_2 as a key taxon, and CST3 was characterized by a core genus, Erwinia ASV_1. Construction of a gut microbial co-occurrence network revealed that the iGWG group exhibited the highest network connectivity density under most stratification conditions, suggesting more complex internal interactions within its gut microbiota. Correlation heatmap analysis indicated that genera such as Ruminococcus ASV_73 were positively correlated with the Body Mass Index (BMI) of pregnant women. Conclusion: This study suggests that maternal gestational weight gain may be associated with differences in neonatal meconium microbiota composition. However, these findings should be considered exploratory and require validation in larger longitudinal cohorts.