Expecting moms who often turn to acetaminophen for their aches and pains are more likely to wind up with kids who have behavioral issues, a new study warns.

Children between the ages of 2 and 4 were more likely to have attention and behavioral problems if their mothers frequently used acetaminophen during pregnancy, researchers found.

“The kinds of behaviors the caregivers reported included things like the child talking out of turn, not paying attention, not being quiet when they were supposed to be quiet, not sitting down when they were supposed to be sitting down, and being a little aggressive with other children,” said researcher Susan Schantz, a professor of comparative biosciences at the University of Illinois Urbana-Champaign.

Acetaminophen — widely known by the brand name Tylenol —  is considered the safest painkiller and fever reducer for pregnancy, but previous studies have found evidence of negative outcomes for children exposed to the medication while in the womb, researchers said in background notes.

For example, a recent study co-led by Schantz linked increased acetaminophen exposure in pregnancy to language delays in children.

For this latest research, investigator asked pregnant women about their acetaminophen use six times during the course of their pregnancy, to capture a more precise picture of drug exposures.

The team then followed the children born of these pregnancies, asking caregivers dozens of standard questions about behavior and attention at ages 2, 3 and 4.

More than 300 children were assessed at age 2, with 262 assessed again at 3 and 196 tested at age 4.

“Our most important finding was that with increasing acetaminophen use by pregnant participants, especially during the second trimester, their children showed more attention-related problems and ADHD-type behaviors, which we call ‘externalizing behaviors,’ at every age we measured,” said co-lead author Megan Woodbury, a postdoctoral researcher at Northeastern University in Boston.

Schantz stressed the findings aren’t an indication that the children have ADHD or that they will be diagnosed with ADHD at a later date.

However, the kids are having more trouble with attention than peers of the same age who were exposed to less or no acetaminophen in the womb.

Woodbury herself is pregnant, and she has herself turned to acetaminophen once per trimester. These findings shouldn’t scare other women away from the medication, which can be effective in treating extreme headaches, pain and fever, she said.

But Woodbury said she chooses not to use the drug for minor aches and pains or slight fevers.

More research is needed to focus on the second trimester and confirm that more frequent use of acetaminophen has an effect on the developing brain, researchers said.

The new study was published recently in the journal Neurotoxicology and Teratology.

More information

The March of Dimes has more on the use of over-the-counter medicines during pregnancy.

SOURCE: University of Illinois Urbana-Champaign, news release, Jan. 16, 2024