Poster Presentation ESA-SRB-ANZOS 2025 in conjunction with ENSA

The association between antibiotic exposure before and during pregnancy and the risk of ADHD in children: A cohort-based study of trimester-specific effects (128721)

Sofie Sonne Westergaard Pedersen 1 2 , Fanney Thorsteinsdottir 1 2 , Ina Olmer Specht 1 2 , Sofus Christian Larsen 1 2 , Nanna Julie Olsen 1 2 , Berit Lilienthal Heitmann 1 2 3
  1. Section for General Medicine, Department of Public Health, Centre for Health and Society, University of copenhagen, Copenhagen, Denmark
  2. Research Unit for Diet and Health, The Parker Institute, Frederiksberg and Bispebjerg Hospital, Denmark
  3. The Boden Initiative, Charles Perkins Centre, University of Sydney, Sydney, Australia

Antibiotic use during pregnancy is common [1,2], yet its potential impact on the neurodevelopment of the offspring remains uncertain [3–6]. This cohort study investigated whether maternal antibiotic exposure before and during pregnancy is associated with the risk of Attention Deficit Hyperactivity Disorder (ADHD) in children.

Data was derived from the Danish PANDORA cohort, linking national registries on births, prescriptions, and patient diagnoses for 787,035 singletons born 1997–2023. Maternal antibiotic exposure was defined as redemption of antibiotics three months preconception or during any pregnancy trimester. Cox proportional hazards regression estimated crude and adjusted hazard ratios (HR) for ADHD diagnosed between age 2-18 years, adjusting for maternal age, education, origin, and ADHD diagnosis.

Results showed that any antibiotic exposure was associated with a 40% increased ADHD risk in offspring (adjusted HR: 1.40 [95% CI: 1.36-1.45]). Secondary analyses indicated that risk increased with among individuals with >1 prescriptions and varied slightly by timing with the risk being highest in the preconception period and second trimester (adjusted HR: 1.43 [1.36-1.50] and 1.44 [1.37; 1.52], respectively). Specific antibiotic subgroups also showed differing associations, with the highest risks observed for certain beta-lactam, penicillins and quinolone compounds. Sensitivity analyses adjusting for maternal smoking and pre-pregnancy BMI yielded similar effect estimates (adjusted HR: 1.25 [1.20-1.30]).

These findings add to the growing concern over the rising prevalence of mental disorders in children [7,8] and underline that maternal antibiotic use before and during pregnancy may modestly increase ADHD risk, reinforcing the importance of carefully weighing indication, timing, and necessity when prescribing antibiotics to women of childbearing age.

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