Sibling control analyses found no evidence that acetaminophen use during pregnancy was associated with children’s risk of autism, ADHD, or intellectual disability. This suggests that the small increase in children’s risk of neurodevelopmental disorders associated with acetaminophen use observed in statistical models without sibling control may have been due to unmeasured confounding. In addition, sibling control analyses did not identify a dose-response association between acetaminophen and neurodevelopmental disorders.
Results of this study indicate that the association between acetaminophen use during pregnancy and neurodevelopmental disorders is a noncausal association. Birthing parents with higher acetaminophen use differed in many aspects from those with lower use or no use. Results suggested that there was not one single “smoking gun” confounder, but rather that multiple birthing parents’ health and sociodemographic characteristics each explained at least part of the apparent association. The null results of the sibling control analyses indicate that shared familial confounders were involved, but do not identify the specific confounding factors.