Large 2026 Cohorts Reaffirm No Link Between Prenatal Acetaminophen and Autism or ADHD

The 2025 Trump administration statement triggered FDA label revisions despite prior observational signals being weak and confounded. Two 2026 registry studies now dominate the evidence base. The Hong Kong cohort tracked exposure timing dosage and pattern across 43 percent of pregnancies while the Danish registry followed 1.5 million births including 31098 exposed children. Both null results align with a 2026 systematic review and meta-analysis that likewise reported no elevation in autism ADHD or intellectual disability risk.

Earlier positive findings largely reflected confounding by indication because fever infection or chronic pain that prompt acetaminophen use also correlate with neurodevelopmental outcomes. Sibling controls in the Hong Kong analysis and the sheer size of the Danish sample reduce that bias substantially. ACOG correctly noted that alarmist messaging harms patients who need safe analgesia during pregnancy.

Regulatory inertia persists because label language is slow to reverse. Future work should examine genetic susceptibility subgroups and objective exposure biomarkers rather than prescription records alone. No randomized trial is feasible so well-powered negative-control designs remain the practical standard.