Comprehensive Analysis of Maternal and Infant Microbiome Profiles: Maternal Microbial Transmission Shapes Offspring Somatic Growth Trajectory

Early-life microbiome development influences somatic growth, yet the role of maternal-to-infant microbial transmission in shaping growth trajectories remains unclear. In a prospective birth cohort of 2,090 mother–infant dyads (13,729 fecal samples, from the first trimester of pregnancy through infancy to 3 years of age), infants were classified into physiological regulation (Trajectory 1), stable (Trajectory 2), and catch-up (Trajectory 3) growth trajectories. We found growth trajectories were significantly associated with maternal microbiome composition before delivery; Bacteroides thetaiotaomicron was enriched in mothers in Trajectory 1 and in their offspring. In contrast, Bifidobacterium pseudocatenulatum exhibited a complex pattern: despite significantly lower maternal abundance and transmission in Trajectory 3, infants in Trajectory 3 displayed comparable or higher abundance by 36 months. Functionally, transmitted B. pseudocatenulatum genomes from Trajectory 3 dyads carried higher counts of glycoside hydrolase and glycosyltransferase genes, which correlated positively with bacterial abundance and offspring somatic growth. Together, we identify a compensatory colonization process in which a limited number of transmitted B. pseudocatenulatum strains with extensive carbohydrate metabolic capacity are selectively retained and amplified.