Acetaminophen and the Risk of ADHD

Health Writer

Acetaminophen has, for many years, been considered a safe option for pain and fever during pregnancy.

But a few recent studies, completed in 2014 and 2016, question the safety of this over-the-counter medication. They point to a possible association between taking acetaminophen during pregnancy and an increased risk of ADHD and autism.

For the 2014 study, researchers looked at more than 64,000 live births using the Danish National Birth Cohort from 1996-2002. The results used a combination of parent-reported behavioral problems before the age of seven, diagnoses from hospital registries and ADHD prescriptions. More than half of all the mothers reported taking acetaminophen at some time during their pregnancy. The study showed that use of acetaminophen was associated with a higher risk of ADHD diagnosis or problem behaviors, with the risk increasing for mothers who used the medication in more than one trimester.

One 2016 study was completed in Spain and included more than 2,600 mothers, of which 40 percent self-reported acetaminophen use during pregnancy. The children were assessed at one-year-old and five-years-old. Researchers found that the children whose mother reported taking the medication during pregnancy had a higher risk of hyperactivity and impulsivity symptoms. The risk increased in both males and females for ADHD, although males were most affected when looking at autism symptoms.

A third study, published in JAMA Pediatrics in August, 2016 looked at about 7,800 women in England and compared behavioral symptoms in children whose mothers did and did not take acetaminophen during pregnancy. Like the other studies, this one also found that children whose mothers took the medication during pregnancy had an increased risk of hyperactivity and behavioral problems.

Researchers from the 2014 study think that the increase in our understanding of ADHD does not justify the increase in the diagnoses over the past several decades. They say there must be additional environmental factors contributing to the rise in ADHD diagnoses. Acetaminophen might help explain it. They do admit that their study has limitations, for example, some of the mothers were not able to accurately provide information on the dosage of the acetaminophen or pinpoint exactly which week it was taken during pregnancy and that "further studies are needed."

There are also some questions about the validity of the 2016 Danish study. According to an article in the Independent, “Scientific experts have dismissed claims” from this study.

The participants (mothers) in this study self-reported use of acetaminophen during two interviews during their pregnancy: at 12 weeks and 32 weeks. The results were based on the mother’s recollection of taking the medication. For example, at the 32-week interview, mothers were asked to recall when and how much acetaminophen had been taken over the past 20 weeks. Some were not able to recall the exact dose taken. This, according to some experts, means there is not sufficient data to make a conclusion about the connection between the medication and the risk of either autism or ADHD.

Should you be worried?

Dr. Evie Stergiakouli, the lead author of the most recent study, indicated to ABC News that the “effect overall was small.” Women who are pregnant do not need to immediately stop taking acetaminophen, especially if they have a fever.

The best course of action is to talk to your doctor before taking any medication, even acetaminophen, while you are pregnant.

Eileen Bailey is a freelance health writer. She is the author of Idiot's Guide to Adult ADHD, Idiot's Guide to Cognitive Behavioral Therapy, Essential Guide to Overcoming Obsessive Love and Essential Guide to Asperger's Syndrome. She can be found on Twitter @eileenmbailey and on Facebook at eileenmbailey.