Overview
- The Hong Kong study, published June 29, 2026, used sibling-matched analyses and found no association between prenatal acetaminophen exposure and autism (adjusted HR 1.00) or ADHD (adjusted HR 1.01).
- Researchers analyzed electronic health records from 2001–2023 starting with about 708,000 mother–child pairs and focused sibling comparisons that included roughly 124,000 children for autism and 97,000 for ADHD with around 10 to 11 years median follow-up.
- The team used negative-control tests of acetaminophen use before pregnancy and dose and timing checks and found similar modest associations in standard cohort analyses but no effect in sibling comparisons, which points to confounding by maternal health or family factors rather than a causal drug effect.
- Study limits include reliance on prescription records from Hong Kong’s public system that may miss over-the-counter and private-sector acetaminophen use and the possibility of residual confounding even after sibling matching.
- The new results match prior sibling-comparison studies in several countries and a Danish analysis, offer reassurance for pregnant people and clinicians, and bolster current guidance that recommends acetaminophen for fever and pain in pregnancy while noting remaining data gaps.