Influence of Gestational Diabetes Mellitus on Neonatal Gut Microbiota; a Systematic Review of Studies Based on Meconium Analysis Publisher



Atarod M H ; Zakeri Rad L ; Bagheri Chime S ; Bairamzadeh E
Source: Immunopathologia Persa Published:2026

Abstract

Introduction: In recent years, gestational diabetes mellitus (GDM) has been recognized as one of the most common metabolic disorders during pregnancy, attracting considerable research attention. This systematic review focuses on high-quality studies utilizing meconium samples to elucidate the impact of GDM on the initial establishment of the neonatal gut microbiome and its potential role in the development of future metabolic disorders. Material and Methods: This systematic review, conducted in accordance with PRISMA 2020, included observational studies (cohort, case-control, and cross-sectional) examining the association between maternal GDM and neonatal gut microbiota using meconium samples. Studies published in English or Persian without time limitation were considered. Outcomes focused on microbiota composition differences, and searches were performed across PubMed, Scopus, Web of Science, Embase, and Google Scholar to ensure comprehensive literature coverage. Results: A total of 11 studies (5 cohorts, 4 case-control, 1 cross-sectional, and 1 longitudinal) were included. Across all designs, meconium collected ≤24 h post-delivery showed consistent α-diversity reduction and distinct β-diversity in GDM-exposed infants. Proteobacteria and Escherichia-Shigella, Firmicutes, Bacteroidetes, Bacteroides, Lactobacillus, and short-chain fatty acids (SCFAs) (acetate, propionate, butyrate) levels were significantly decreased, accompanied by down-regulation of short-chain fatty acids synthesis pathways and up-regulation of oxidative stress and lipopolysaccharide biosynthesis functions. Conclusion: This review shows that GDM significantly alters the neonatal gut microbiota, with reduced microbial diversity, increased Proteobacteria and Escherichia-Shigella, and decreased SCFA-producing bacteria (Bacteroides, Lactobacillus). Functional analyses revealed suppressed SCFA synthesis, enhanced inflammatory and oxidative pathways, and weakened intestinal barrier integrity (P < 0.05), linking maternal hyperglycemia to early dysbiosis and long-term metabolic risk. Copyright © 2026 The Author(s); Published by Nickan Research Institute. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.