A MOTHER’S gut microbiome is a major new research
The large longitudinal study found that the maternal gut microbiome is a central influence on early-life microbial development and health, providing new insights into how maternal and early-life factors shape the developing infant gut
Gut Microbiome is the Largest Influence
Researchers investigated the dynamics of the maternal gut microbiome of 714 mothers, all who were participating in the Dutch Lifelines NEXT birth cohort, by taking faecal samples during pregnancy, at birth and 3 months post-partum
Analyses at all three stages found that the maternal gut microbiome remained relatively stable throughout pregnancy and the postpartum period, with only subtle changes in bacterial composition
In contrast, through testing faecal samples from the infants at two weeks, one, two, three, six, and 12 months of age, they found that the infant microbiome underwent substantial change and maturation during the first year of life
The researchers also performed ultra-deep sequencing of maternal vaginal and breast milk microbiomes, alongside 474 clinical, dietary and environmental variables
They concluded that a substantial proportion of infant gut strains were identical to maternal gut strains, emphasising that the maternal gut, rather than the vaginal or breast milk microbiomes, is the primary reservoir for infant colonisation
Transmission of specific bacteria between mother and child was more frequent when that bacterial species was abundant in the maternal gut, and was greatest early in infancy
Another major finding of the study was that the maternal gut microbiome can predict infant eczema. The researchers found that the composition of the maternal gut microbiome and levels of various bacteria could predict which infants would go onto develop eczema within the first year of their life, although the mechanisms underlying this association remain unclear
Delivery and Feeding Were the Strongest Influences
Mode of delivery was found to be one of the strongest factors associated with the development of the infant gut microbiome. Infants born vaginally had greater representation of certain Bacteroides species compared with those born by caesarean section, highlighting the influence of birth mode on early microbial colonisation
Feeding mode was another major factor, with breastfeeding associated with distinct microbial and carbohydrate-metabolising profiles compared with formula feeding. These effects became less pronounced following the introduction of solid foods
Interestingly, the place of birth appeared to have only a modest effect and home versus hospital delivery was much less strongly associated with microbiome composition than delivery or feeding mode
Implications for early-life health
These findings reinforce the concept that infant microbiome development is a dynamic process shaped by multiple factors, including maternal biology, birth and nutrition
Importantly, the microbiome observed at two weeks did not reliably predict its composition later in infancy, suggesting that early colonisation does not necessarily determine the longer-term microbial trajectory
The findings raise intriguing possibilities for future preventive strategies targeting the maternal microbiome while also underscoring the need for further research into the relationship between maternal microbiome and infant health outcomes
Reference
Sinha T et al. Maternal influences on infant gut microbiome and health. Nature, 2026 https://doi.org/10.1038/s41586-026-10922-9
Featured image: leszekglasneron AdobeStock
Author:
Cecilia Adamou
