New Reason to Fear Acetaminophen: ADHD New study finds use during pregnancy is linked to 'ADHD-like behaviors' By Evann Gastaldo, Newser Staff Posted Feb 25, 2014 11:19 AM CST 15 comments Comments Stock image (Shutterstock) (Newser) – The bad news about acetaminophen just keeps on coming: A new study finds that use of the drug during pregnancy is linked to "ADHD-like behavioral problems" in children, CNN reports. The Danish study looked at data from more than 64,000 children and found that those who had prenatal exposure to acetaminophen had a 13% higher risk of exhibiting ADHD-like behaviors, a 29% higher risk of being prescribed ADHD medication, and a 37% higher risk of receiving a diagnosis of hyperkinetic disorder, a severe form of ADHD, USA Today reports. The risk increased the later in pregnancy the drug was taken and the longer it was taken. Women who used acetaminophen for 20 weeks or longer had a 50% higher chance of their children being prescribed ADHD medication. But the authors did not find a cause-and-effect relationship, and they note that "exhibiting ADHD-like behaviors" is not the same as actually having ADHD. Right now, doctors consider acetaminophen the "safest" pain reliever for pregnant women, NBC News reports; the study author says pregnant women "shouldn't worry at this point." What could account for the link? The authors think acetaminophen may interfere with key maternal hormones that impact fetal brain development. Another recent study also found that frequent acetaminophen use during pregnancy was linked with a 70% higher risk of behavioral problems in children.