A new study suggests that there is a critical period in late pregnancy when the foetus is particularly vulnerable to the effect of paracetamol. (Photo: Shutterstock)

Paracetamol may increase risk of ADHD

A new study indicates that the risk of giving birth to a child with ADHD increases if women take paracetamol during pregnancy.

Lise Brix

Published 2 March 2014 - 06:11

Most of us know the paracetamol from over-the-counter painkillers. The substance is generally considered harmless for pregnant women, but a new study indicates that it may harm the foetus if the mother takes paracetamol during pregnancy.

The study suggests that taking paracetamol during pregnancy may increase the child’s risk of developing ADHD.

“It appears that women who take paracetamol during pregnancy are slightly more likely to give birth to children with ADHD. In the study, the risk of having children with ADHD increases by 10-30 percent for women who have taken paracetamol,” says Professor Jørn Olsen, of the Department of Public Health at Aarhus University, Denmark.
He co-authored the new study, published in the journal JAMA Pediatrics.

The more pills, the higher the risk

The data in the study reveals that the more pills with paracetamol the women ate during pregnancy, the greater the risk of their child developing ADHD.
The risk is highest if the woman took the painkillers in late pregnancy.

”This may indicate that there is a critical period in late pregnancy when the foetus is particularly vulnerable to the effect of paracetamol,” says Olsen.

The study is based on data from 64,000 pregnant women who participated in the ‘Bedre sundhed for mor og barn’ (Better health for mother and child) research project.

The women were pregnant during the period 1996-2002, and their children have now reached an age at which it is possible to determine how many of them have been diagnosed with ADHD.

Correlation yet to be proven

The Danish researchers are the first in the world to find a correlation between paracetamol intake and the development of ADHD. Professor Olsen is, however, keen to point out that further studies are needed before anything can be said with certainty about this correlation.

According to the study data, “it cannot be ruled out” that paracetamol is the ‘cause’ of two extra cases of ADHD for every 100 children that are born, he says.

“Most of the women who took paracetamol had babies without ADHD. You could say that if seven out of 100 baby boys get ADHD, then the figure would perhaps be 8-9 out of 100 baby boys if the mothers took paracetamol.

“So for the individual woman there may not be such a great risk, but at the societal level we’re talking about a lot of children, and that can be costly,” says Olsen, pointing out that the past few decades have seen a great increase in the number of children diagnosed with ADHD.

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Read the Danish version of this article at videnskab.dk