LAUSR

Introduction Acetaminophen is the only analgesic recommended for use during pregnancy. This use has recently been linked to childhood developmental disorders, a finding that requires further investigation. Adverse birth outcomes—preterm birth, low birthweight, and small for gestational age—are associated with increased risk of developmental disorders and can serve as intermediate outcomes when examining the impact of maternal acetaminophen use. Methods Clinical and lifestyle-factor data were gathered from 1200 women within the Ontario Birth Study who delivered between January 2013 and June 2017. Poisson regression with robust error variance was used to estimate the relationship between acetaminophen use before and during pregnancy and low birthweight, preterm birth, and small for gestational age. Results Offspring of mothers who used acetaminophen before pregnancy had a higher risk of low birthweight and small for gestational age. Acetaminophen use