New research suggests that exposure to specific bacteria and older siblings can help restore the infant gut microbiome balance within the first year of life, particularly for babies born via Cesarean section (CS).
The infant gut microbiome is crucial for immune development, and disruption following CS has been linked to an increased risk of childhood asthma.
In a study of 700 children, researchers developed a "restoration score" to measure how closely a 1-year-old's gut microbiome resembled that of vaginally delivered infants. Early microbial patterns at one week of age proved to be a predictor of the restoration score at one year.
Infants with older siblings showed significantly higher restoration scores. This association appears to stem from increased exposure to beneficial bacteria, likely transferred through close household contact. These findings were replicated in an independent Canadian cohort.
The study suggests that microbiome disruption from CS delivery may be modifiable. Early bacterial exposures in the first weeks of life seem to influence the development of a more typical microbiome profile by one year. While this observational study cannot confirm causality, it highlights the dynamic nature of the infant gut microbiome and the potential role of sibling exposure in its development after CS delivery.