Prenatal Use of Acetaminophen and Child IQ: A Danish Cohort Study.

Background: Acetaminophen (paracetamol) is the most commonly used pain and fever medication during pregnancy, and recently has been linked to hyperactivity and behavioral problems in children. We examine whether prenatal use of acetaminophen affects children's intelligence quotient (IQ).

Methods: We studied 1,491 mothers and children enrolled in the Danish National Birth Cohort (DNBC; 1996-2002). Acetaminophen use in pregnancy was prospectively recorded in three telephone interviews. Child IQ was assessed at age 5 with the Wechsler Primary and Preschool Scales of Intelligence-Revised (WPPSI-R) administered by trained psychologists. We employed linear regression analysis, adjusting for maternal IQ and other confounding factors, and assessed interactions between acetaminophen and indications for use.

Results: Both maternal fever in pregnancy and acetaminophen use were associated with child IQ. Children born to mothers using acetaminophen without reporting fever scored on average 3.4 points lower (95% confidence interval [CI]: 0.30 to 6.6 points) on performance IQ compared with offspring of mothers who neither experienced fever nor took acetaminophen. Estimated effects for acetaminophen were stronger for first or second trimester use. Children born to mothers reporting fever without using acetaminophen also scored lower on verbal (2.7 points, 95% CI: -0.19, 5.6) and performance IQ (4.3 points, 95% CI: 0.30, 8.3); IQ scores were not affected if mothers with fever used acetaminophen.

Conclusions: Maternal acetaminophen use during pregnancy was associated with lower performance IQ in 5-year olds. However, acetaminophen treatment of maternal fever in pregnancy showed an apparent compensatory association with child IQ scores. (See video abstract at http://links.lww.com/EDE/B87.).