Comment from Anonymous

Please consider the attached comment regarding the compilation of biomarker-based prenatal acetaminophen exposure studies in support of the precautionary warning requested in the citizen petition. This comment reviews the biomarker-based evidence collectively and highlights that, when these studies are evaluated together, the overall pattern of findings is concerning. Biomarker-based exposure assessment is particularly important because it helps address one of the major criticisms frequently directed at the prenatal acetaminophen literature: maternal recall bias and exposure misclassification. Unlike retrospective self-reporting studies alone, biomarker studies evaluate direct biological evidence of fetal acetaminophen exposure during pregnancy. When viewed collectively, these biomarker studies show a consistent signal of association with adverse neurodevelopmental outcomes across multiple cohorts and methodologies. This is significant because it strengthens the argument that the associations observed in the broader epidemiologic literature may reflect genuine biological effects rather than artifact resulting from study design limitations. Under a precautionary principle framework, this body of biomarker evidence further supports the need for clearer prenatal risk communication and warning language so that pregnant women and clinicians can make more fully informed decisions regarding acetaminophen use during vulnerable periods of fetal development.