As if it weren’t difficult enough to follow all the rules for improving the chances of both a safe pregnancy and a healthy baby, now there’s evidence that pregnant women who take acetaminophen (Tylenol and many other brands) to relieve pain or reduce fever might be raising the risk of bearing a child later diagnosed with attention deficit hyperactivity disorder (ADHD).
A study published in JAMA Pediatrics showed a 40% higher chance of such a diagnosis for children whose mothers took acetaminophen during pregnancy versus those who didn’t.
As explained by the Los Angeles Times, the study doesn’t establish that prenatal exposure to acetaminophen caused the observed increase in diagnosed hyperactivity disorders, prescriptions for ADHD medications or emotional problems in children reported by parents. But the study was designed to address shortcomings of other studies that find an association between an environmental exposure and the appearance of a specific outcome years later.
More than 64,000 Danish mothers and their children were study subjects. Information was collected about pregnant subjects’ acetaminophen use long before problems in their children’s learning or behavior would have become evident. That enabled researchers to avoid what’s called “recall bias” — you can’t pre-judge something you don’t know will happen.
Pediatric subjects were studied from their first trimester in utero for as long as 15 years. In addition to surveying parents about their children’s strengths and weaknesses, the researchers used comprehensive, reliable databases (registries of physician diagnoses and dispensed pharmacy prescriptions) to measure ADHD within the population.
The study concluded that the probability of a child developing ADHD symptoms severe enough to require medication jumped by more than 60% if his or her mother took acetaminophen during the last two trimesters of pregnancy; it rose by almost 30% if acetaminophen was taken only in the third trimester. If mom took the drug during only the first trimester, the increased risk was about 9%.
Because a pregnant woman’s high fever and infection can be dangerous for her fetus, an editorial accompanying the study advised that women and their doctors shouldn’t reject acetaminophen solely based on this study. It said that more information is needed on how acetaminophen might promote ADHD later, when and who is most likely to be affected. The current findings, it advised, “should be interpreted cautiously and should not change practice.”
So what’s a prospective mother to do?
Even medicine deemed safe carries risks, and doubly so for pregnant women. The safest approach is to take the lowest possible dose as seldom as possible, said Dr. Daniel Kahn, a maternal-fetal health specialist interviewed by The Times. He was not involved in the study.
If it doesn’t work, you have to discuss options with your doctor. Kahn added that the study “certainly wouldn’t stop me from treating a fever,” noting that unchecked fevers have been associated with several poor health outcomes in babies, including lowered IQs.
Acetaminophen has gotten some bad publicity of late, largely due to confusing dosing. To understand how to make the most of this medicine without undue risk, see our blog, “Understanding Acetaminophen and How to Make It Safer.”