As an attorney that handles both product liability cases and birth injury medical malpractice cases, this story shocked me. According to a new study published in JAMA Pediatrics, acetaminophen used during pregnancy—the key ingredient in Tylenol and other pain and fever drugs—may be linked to ADHD in children. Researchers found that children of mothers who used acetaminophen during pregnancy were 37% more likely to be diagnosed with hyperkinetic disorders, 29% more likely to use ADHD medications, and 13% more likely to exhibit ADHD-like behaviors at age 7 years. According to The LA Times “the risk increased the most – by 63% – when acetaminophen was taken during the second and third trimesters, and by 28% when used in the third trimester alone.” When taken just during the first trimester, however, “the added risk was 9%.” The study came out of Denmark where over 64,000 women participated and over half took the drug during pregnancy. The drug is thought to interfere with hormone systems that ultimately alter brain development. Correlation does not necessarily mean causation. As The USA Today reports, more study is needed to prove a cause and effect relationship, but pregnant women will no doubt think twice now about using acetaminophen.