Acetaminophen in Pregnancy and Attention-Deficit and Hyperactivity Disorder and Autism Spectrum Disorder

Acetaminophen is a common over-the-counter medication that recently gained substantial media attention regarding its use by pregnant individuals. In this clinical perspective, we discuss the strengths and limitations of the published literature on the effect of maternal acetaminophen use in pregnancy on the child's risk of developing attention-deficit and hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Studies included were specifically selected on the basis of the quality and validity of ADHD or ASD outcome definitions. From a total of 56 identified studies, commentaries, and editorials of relevance, we critically reviewed nine studies with original data that satisfied our inclusion criteria and three meta-analyses. Most studies that have reported positive findings are difficult to interpret because they have important biases, notably a high degree of selection bias, variability in selection and adjustment for various potential confounders, and unmeasured familial confounding. When unobserved familial confounding through sibling analysis was controlled for, associations weakened substantially. This suggests that residual confounding from shared genetic and environmental factors may have caused an upward bias in the original observations. According to the current scientific evidence, in utero exposure to acetaminophen is unlikely to confer a clinically important increased risk of childhood ADHD or ASD. The current level of evidence does not warrant changes to clinical guidelines on the treatment of fever or pain in pregnancy. Prospective research designed to account for familial and psychosocial environmental factors related to both maternal use of acetaminophen and children's neurodevelopment should be undertaken.