Overview
- The large Hong Kong study published June 29 used 2001–2023 electronic health records and found no association between prenatal acetaminophen and autism or ADHD in sibling-matched analyses.
- Conventional cohort analyses within the same dataset showed modest positive associations, but those signals matched effect sizes for pre-pregnancy use in negative-control tests and disappeared in sibling comparisons.
- Sibling-matched analyses included about 124,333 children for autism and 97,285 for ADHD and work by comparing siblings with different in‑utero exposure to control for shared genetics and family environment.
- Researchers cautioned that the study mainly captured prescribed acetaminophen in Hong Kong’s public system and therefore may undercount over‑the‑counter and private‑sector use, and sibling designs cannot remove all nonshared confounders.
- The findings align with prior sibling and Danish studies and reduce evidence for a causal drug effect, which supports existing obstetric guidance that acetaminophen is an acceptable option for indicated use in pregnancy.