Exposure of infants to antibiotics via cord blood, breast milk, and formula: A review on exposure level, temporal variation, and risk assessment

The pervasive use of antibiotics across various sectors, including agriculture, medicine, and aquaculture, has led to a notable increase in environmental antibiotic residues. This phenomenon has raised significant public concern regarding the potential health risks antibiotics may pose, particularly to vulnerable populations such as infants. However, the conceptualization of exposure routes of antibiotics to infants and the associated health risks has not been conducted. This review summarized three main pathways infants are exposed to antibiotics, including umbilical cord blood, breast milk, and infant formula. Antibiotic exposure levels in infants were synthesized, examining spatial and temporal trends in antibiotic concentrations across different media through clinical testing. We also analyzed the doses of antibiotics consumed by infants over time through breast milk and formula, evaluating the associated risks. Furthermore, we explored the potential adverse effects of early-life antibiotic exposure on the infant gut microbiota, physical development, and multiple organ systems. Given the global significance of antibiotic distribution, it is pertinent to comprehensively monitor antibiotic concentrations in infants and conduct longitudinal follow-up studies on their growth and development, accurately quantifying and assessing the impacts on fetal and infant health.