EARLY-LIFE ANTIBIOTIC EXPOSURE AND ITS INFLUENCE ON THE GUT–BRAIN AXIS: IMPLICATIONS FOR COGNITIVE AND EMOTIONAL DEVELOPMENT IN CHILDREN

Background: The first 1,000 days of life represent a critical window for gut microbiome development. Increasing evidence suggests that early-life antibiotic exposure disrupts microbiome maturation, enhances the gut resistome, and predisposes children to adverse health outcomes. Objective: This systematic review aims to evaluate the effects of early-life antibiotic exposure on gut microbiome diversity, resistome amplification, and subsequent childhood health conditions such as allergies, obesity, and neurodevelopmental disorders. Methods: Following PRISMA 2020 guidelines, we systematically reviewed 10 peer-reviewed studies published from 2010–2024. Eligible studies included human infants or children exposed to systemic antibiotics in the first two years of life and assessed outcomes in microbiome composition, ARG profiles, or long-term health status. Results: Antibiotic exposure was consistently associated with reduced gut microbial diversity, loss of beneficial taxa (e.g., Bifidobacterium), and increased ARG burden. Several cohort studies linked early antibiotic use with asthma, allergic rhinitis, ADHD, obesity, and delayed neurodevelopment. These effects were context-dependent and particularly severe in LMICs with high antibiotic misuse. Conclusion: Early-life antibiotics disrupt gut microbial ecology, promote antimicrobial resistance, and elevate risks for chronic health conditions in children. Improved stewardship and targeted interventions are essential to mitigate long-term harm.