Early-life antibiotics, gut microbiota, and later health in children

Children are commonly exposed to antibiotics in utero, at birth, and during childhood. The most common reason for antibiotic exposure during vaginal birth is intrapartum antibiotic prophylaxis, administered for Group B Streptococcus (GBS)-colonized mothers to prevent severe neonatal early-onset GBS infections. My thesis explores the association of early-life antibiotic exposure with children’s gut microbiota, and later health.

The first study compared the effects of perinatal antibiotics and childhood antibiotic courses on gut microbiota composition in the first year of life in a prospective cohort study of 100 vaginally delivered children. Perinatal antibiotic exposure was associated with alterations in the infant’s gut microbiota at 1 year of age, alterations that were greater than those of exposure to courses of antibiotics during the first year of life (study 1).

The second and third study were population-based and register-based studies of over 40,000 vaginally delivered children born in Oulu University Hospital and Oulaskangas Hospital. They investigated the association of early-life antibiotics and children’s later immune-related diseases, overweight and obesity. Perinatal antibiotic exposure was associated with an increased risk of autoimmune disease diagnoses in childhood, whereas no association with the diagnosis of allergic diseases or obstructive airway diseases was observed. Childhood antibiotic exposure in the first two years of life was associated with increased risk of childhood overweight and obesity. No similar association was observed with with antibiotic exposure before or during pregnancy or during the perinatal period.