A study in the November 2017 Pediatrics found long-term use of acetaminophen during pregnancy, as well as extended use of the common over-the-counter pain medicine by fathers, was associated with twice the risk of Attention Deficit Hyperactivity Disorder (ADHD) in children.
At the same time, the Norwegian study, "Prenatal Exposure to Acetaminophen and Risk of ADHD," which will be published online Oct. 30, found short-term prenatal acetaminophen use of a week or less was associated with decreased rates of ADHD.
The study does not provide definitive evidence for or against a causal relation between maternal use of acetaminophen, which is the recommended medication for pregnant women with fever or pain and is used by an estimated 65 percent to 70 percent of pregnant women in the United States. However, authors say the association they found calls for further study and more cautious consideration of its use during pregnancy.
For the study, researchers examined data from 112,973 children in the Norwegian Mother and Child Cohort Study, including 2,246 with an ADHD diagnosis. After adjusting for mothers' use of acetaminophen before pregnancy, family risk factors for ADHD, and other circumstances, researchers found prenatal acetaminophen use of less than 7 days was negatively associated with ADHD in children. For use lasting more than 7 days, the risk of children being diagnosed with ADHD increased with the number of days exposed; those who had 29 or more days of prenatal acetaminophen exposure were more than twice as likely to be diagnosed with ADHD. The data also showed children whose mothers took acetaminophen for fever and infections for 22 to 28 days were six times more likely to have ADHD. Among other findings, fathers who had taken acetaminophen for 29 or more days prior to conception had twice as many children with ADHD.
Editor's note: The solicited commentary, "An Association between Prenatal Acetaminophen Use and ADHD: the Benefits of Large Data Sets," accompanies this study.
Additional Information from HealthyChildren.org: