To conduct a scoping review to examine the relationship between a diagnosis of gestational diabetes mellitus (GDM) and the neonatal and infant gut microbiome from 0 to 1 year of age.

We searched PubMed, Scopus, Embase, and CINAHL for articles with key terms “microbiome” and “gestational diabetes mellitus.”

We included articles published in English in peer-reviewed journals between 2012 and 2021 that were reports of original research studies in which researchers used next-generation sequencing for analysis of the fecal microbiome and collected meconium or transitional stool from neonates and infants.

We identified nine studies with a combined sample size of 1,279 neonates and infants. We extracted data, including title, authors, sample size, study design, methods, findings, significance, and limitations. We extracted and charted confounding variables such as treatment of GDM, body mass index, gestational age at birth, antibiotic use, mode of birth, and feeding method.

Gestational diabetes mellitus may alter the neonatal and infant gut microbiome because neonates and infants of women with GDM had altered composition and diversity compared to neonates and infants of women without GDM.

Mechanisms by which the neonatal and infant microbiome changes in response to GDM are poorly understood and need to be evaluated in future research. Further study of how GDM plays a role in the initial seeding of the microbiome, how the maternal microbiome may affect fetal metabolic programming, and how the neonatal microbiome leads to the future development of obesity and glucose intolerance is critical. Future studies should include larger sample sizes, appropriate collection of potential confounding variables, assessment of maternal interventions for GDM, and longitudinal designs to further understand potential associations with long-term detrimental outcomes such as obesity and impaired glucose tolerance.