Rationale

Antibiotics are commonly prescribed for infants. In addition to increasing concern about antibiotic resistance, there is a concern about the potential negative impact of antibiotics on the gut microbiota and health and development outcomes.

Objective

The aim of this study was to investigate the association between early life antibiotic exposure and later neurocognitive outcomes.

Methods

Participants were infants born to mothers enrolled in the probiotics study. The initial study was designed to evaluate the effect of two different probiotics on allergy outcomes in childhood. Antibiotic exposure was based on parent report and categorised according to the following timing of the first exposure: 0–6 months, 6–12 months, 12–24 months or not at all. At 11 years of age, children’s neurocognitive outcomes were assessed using psychologist-administered, parent-report and self-report measures. The relationship between the timing of antibiotic exposure and neurocognitive outcomes was examined using regression models.

Results

Of the 474 participants initially enrolled, 342 (72%) children had a neurocognitive assessment at 11 years of age. After adjustment for mode of delivery, probiotic treatment group assignment, income and breastfeeding, children who had received antibiotics in the first 6 months of life had significantly lower overall cognitive and verbal comprehension abilities, increased risk of problems with metacognition, executive function, impulsivity, hyperactivity, attention-deficit hyperactivity disorder, anxiety and emotional problems.

Conclusions

These results provide further evidence that early exposure to antibiotics may be associated with detrimental neurodevelopmental outcomes.