Maternal obesity modifies the vertical transmission of gut microbiota and metabolites: Insights from mother-infant dyads in a mexican cohort

Maternal obesity is increasingly recognized as an important modulator of early-life microbial and metabolic environments. This study investigates the association between maternal body mass index (BMI) and the microbiota and metabolite profiles of colostrum and neonatal feces in a Mexican mother–infant cohort. Milk and fecal samples were collected from dyads of obese and normal-weight mothers. Bacterial microbiota composition was characterized by sequencing the 16 S rRNA gene (V3 region) using Ion Torrent technology, and metabolomic profiling was performed using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The results provide evidence consistent with vertical microbial and metabolic transmission, with Firmicutes and Patescibacteria predominating in Colostrum. Neonates born to obese mothers exhibited reduced relative abundances of Lactobacillus in neonatal fecal samples, alongside increased levels of Lactobacillus and Staphylococcus in both colostrum and mother´s feces. Overall microbial diversity across maternal stool, colostrum, and neonatal stool samples was not significantly associated with maternal BMI; however, distinct metabolite signatures linked to maternal obesity, like oligopeptides, glycoside-related compounds, Phosphatidic Acid (PA) Derivatives, bioactive molecules such as enkephalinamide derivatives, were observed. These findings highlight the role of breastfeeding as a key interface in shaping the neonatal gut microbiota and metabolome and suggest potential pathways linking maternal metabolic status with early-life microbial and metabolic programming. This study advances understanding of maternal–infant microbial ecology and supports further investigation into the long-term health implications of maternal obesity.