Bertoldi AD, Rifas-Shiman SL, Boing AC, et al. - Using longitudinal data from children ages 2-3 years in Brazil and the United States, researchers estimated the correlations of prenatal and infant exposure to acetaminophen with early childhood cognition. Using the Peabody Picture Vocabulary Test and the Wide Range Achievement of Visual Motor Abilities (WRAVMA), the American Project Viva cohort (1,217 mother-child pairs enrolled 1999-2002) evaluated cognition at about 3 years. The Brazilian 2015 Pelotas Birth Cohort (3818 mother-child pairs) evaluated cognition at 2 years using the INTERGROWTH-21st Neurodevelopment Assessment. In Project Viva, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was linked to lower WRAVMA drawing scores. In Pelotas, however, exposure to acetaminophen in both the 1st and 2nd trimester of pregnancy was not correlated with INTER-NDA motor scores and was related to higher INTER-NDA total scores. Other comparisons showed no evidence of any associations. Inconsistencies and lack of results precision did not clarify the research question given that the authors still have a great variation and ambiguity to identify the risk or safety of early childhood cognition associated with acetaminophen use.