This study used national health insurance records on Korean children born from 2010 to 2017 who had a first health check at 6 months. The full group held 3,163,206 children. A matched set paired 1,142,940 exposed children with the same number of unexposed children. Children were followed for an average of 6.8 years.
Exposure meant a mother being prescribed antibiotics for at least three days in a pregnancy trimester, or a baby getting them in the first six months. Both were linked to a slightly higher chance of a childhood mental health or developmental diagnosis, including ADHD. The link was somewhat larger for children exposed both before and after birth. Comparing brothers and sisters gave a similar small link. The link grew with more and longer prescriptions, but no single trimester stood out.
In the matched group, ADHD was diagnosed in 1.17% of exposed children. Among unexposed children, the share was 1.02%. No link was found for alcohol or drug misuse or compulsive disorders.
The authors say the study shows a link only, not cause, and that the absolute risk is low. The records showed prescriptions, not whether the medicine was taken. Drug effects could not be separated from the effects of the mother's infection. The authors suggest that clinicians weigh the risks and benefits of antibiotics in pregnancy and early infancy case by case.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Oh, 2024: any childhood neuropsychiatric disorder after exposure before birth, matched group, adjusted HR 1.07 (95 % CI 1.05 to 1.08).
- Oh, 2024: any childhood neuropsychiatric disorder after exposure in the first six months, matched group, adjusted HR 1.05 (1.03 to 1.07).
- Oh, 2024: any childhood neuropsychiatric disorder after exposure both before and after birth, versus no exposure, adjusted HR 1.12 (1.09 to 1.15).
- Oh, 2024: ADHD after any antibiotic exposure versus none, matched group, adjusted HR 1.10 (95 % CI 1.07 to 1.13).
- Oh, 2024: sibling comparison, exposure before birth, adjusted HR 1.10 (95 % CI 1.06 to 1.18 in Table 4 and the Results text; the abstract states 6 to 12 percent for this interval, and the two do not agree).
- Oh, 2024: sibling comparison, exposure in the first six months, adjusted HR 1.12 (1.07 to 1.17). What the terms mean:
- Adjusted HR (hazard ratio) compares how often a diagnosis appeared over time in exposed versus unexposed children, after accounting for other factors; 1 means no difference and above 1 means more diagnoses in the exposed group.
- 95 % CI is the range the true value most likely falls in; when the whole range sits above 1, the link is unlikely to be down to chance.
Source: Oh J, Woo H, Kim H, et al.. Prenatal and infant exposure to antibiotics and subsequent risk of neuropsychiatric disorders in children: A nationwide birth cohort study in South Korea. Psychiatry Research (2024). doi:10.1016/j.psychres.2024.116117