February 25, 2014 Updated: February 25, 2014 at 9:54 am
Pregnant women have long been assured that acetaminophen can treat their aches, pains and fevers without bringing harm to the babies they carry. Now researchers say they have found a strong link between prenatal use of the medication and cases of attention-deficit hyperactivity disorder in children.
The results, published Monday in the journal JAMA Pediatrics, add to growing evidence that the active ingredient in Tylenol may influence brain development in utero. But they do not provide clear answers for mothers-to-be or their doctors about whether acetaminophen is safe during pregnancy.
In analyzing data on more than 64,000 Danish women and their children, researchers found that kids whose mothers took the painkiller at any point during pregnancy were 29 percent more likely to be diagnosed with ADHD than were kids whose mothers took none. The risk increased the most — by 63 percent — when acetaminophen was taken during the second and third trimesters, and by 28 percent when used in the third trimester alone. But when taken only in the first trimester, the added risk was only 9 percent.