biostudies-literatureUnknownKelsey CNICHD NIH HHS<h4>Background</h4>An infant's mother is one of the first sources of neonatal microbial colonization, and infant-maternal dyad microbial variations have been linked to childhood behavioral traits and mental health outcomes. However, how the gut microbiome influences mental health, including potential bidirectional relations between mother and child, remains poorly understood.<h4>Method</h4>Using metagenomic sequencing and behavioral questionnaires, we examined within-person and between-person (mother-infant dyad) associations between the gut microbiota and behavior across the first year of postnatal life (N = 121 dyads; N = 514 stool samples).<h4>Results</h4>There were rapid changes in taxa diversity and gut microbiota composition for infants, whereas the maternal microbiome remains relatiPediatric researchhttps://www.ebi.ac.uk/biostudies/studies/S-EPMC12758567biostudies-literatureBidirectional relations between the maternal and infant gut microbiome and behavior.PMC12758567K99 HD115830McCulloch JAGrossmann TTrinchieri GDreisbach CKelsey CYancey HMoulder RAlhusen JPrescott SfalseBidirectional relations between the maternal and infant gut microbiome and behavior.<h4>Background</h4>An infant's mother is one of the first sources of neonatal microbial colonization, and infant-maternal dyad microbial variations have been linked to childhood behavioral traits and mental health outcomes. However, how the gut microbiome influences mental health, including potential bidirectional relations between mother and child, remains poorly understood.<h4>Method</h4>Using metagenomic sequencing and behavioral questionnaires, we examined within-person and between-person (mother-infant dyad) associations between the gut microbiota and behavior across the first year of postnatal life (N = 121 dyads; N = 514 stool samples).<h4>Results</h4>There were rapid changes in taxa diversity and gut microbiota composition for infants, whereas the maternal microbiome remains relati2025-01-01T00:00:00Z2025 Dec2026-06-06T09:37:53.415Z2026-05-28T03:12:20.82ZS-EPMC127585674138755110.1038/s41390-025-04630-9