Use of acetaminophen during pregnancy may lead to the development of attention deficit hyperactivity disorder (ADHD) in the children being born, according to a Norwegian study.

The study which was published in Paediatrics analysed data on an approximate 113,000 children and their parents; including 2,246 kids who were diagnosed with ADHD. The result found that nearly half of the mothers took acetaminophen, more commonly known as paracetamol, at some point during their pregnancy.

In more details, nearly 47% of the women used acetaminophen during their pregnancies: 27% in one trimester, 16% in two trimesters and less than 4% in all three.

"We found that using acetaminophen for 29 days or more during pregnancy gave a 220% increase in risk for ADHD in the child," said lead study author, Eivind Ystrom of the Norwegian Institute of Public Health and the University of Oslo.

"This was after taking medical conditions and risk for ADHD in the family into account."

The result also found that usage of acetaminophen during just one trimester was linked with 7% higher odds of having a child with ADHD, while women who used acetaminophen in two trimesters has 22% higher chances and those who use in all three trimesters have a 27% chance of having a child with ADHD.

“Surprisingly, adjusting for all the medical conditions related to acetaminophen use during pregnancy (e.g. infections and pain) and familial genetic risk for ADHD, children exposed to long-term use of acetaminophen use during pregnancy were more than two times more likely to have ADHD diagnosed by a specialist in a clinic,” claimed Ystrom.

Experts discuss other probable causes

Not everyone agrees to the findings of the study. Dr Antonio Saad, a researcher at the University of Texas Medical Branch in Galveston, remarked that the finding might just merely been to chance.

“One also has to keep in mind that not using acetaminophen can have negative consequences,” expressed Saad. “Other pain and fever medications, such as ibuprofen, should not be used in pregnancy, which leaves narcotics as the only alternatives for pain and no alternatives for fever.”

Pregnant women are usually advised to avoid taking ibuprofen and other painkillers
Pregnant women are usually advised to avoid taking ibuprofen and other painkillers

Dr Chittaranjan Andrade of the National Institute of Mental Health and Neurosciences in Bangalore, India instead believed that the increased risk of ADHD linked to longer use of acetaminophen might also be due to the severity of medical problems women had, not their use of the drug.

On another note, Andrade told Reuters that a serious fever or infection, for example, might be the reason babies developed ADHD, not acetaminophen their mothers took.

“The results of this study do not adduce sufficiently strong data to discourage the use of (acetaminophen) if indicated during any trimester during pregnancy,” said Andrade.

Adding to the list of experts who disagree is Dr Alison G. Cahill, a member of the American College of Obstetricians and Gynaecologists' Committee on Obstetric Practice, who said the study "doesn't add anything to our medical knowledge.

She added that the researchers for the study calculated the number of children diagnosed with ADHD by codes in their medical records instead of using the measured method usually used in diagnosis of ADHD.

"As you can imagine, there can be some disconnect between the making of that diagnosis and how it's actually coded," Cahill said.

Cahill explained that when linking a prenatal exposure to a certain outcome, scientists would expect to see certain things if the "association is actually true" like repeated results in different studies.

"The other thing we expect to see is a dose-response relationship, where an increasing dose would relate to a worsening risk or worsening severity of that disease," highlighted Cahill.

Is acetaminophen safe?

Cahill stated that acetaminophen taken at low doses reduces risk of ADHD in offspring instead, while at high doses, the reverse is true.

Ystrom also pointed out that pregnant women who need medicine for fever or pain relief "should not refrain from short-term acetaminophen use." He, however advices that pregnant woman who requires "continuous acetaminophen for a longer period" should consult with their physicians.

Ystrom believes that the statistics of her findings holds a significant value. However, sheagreed that more study needs to be done in determining whether or not acetaminophen is responsible for ADHD development in foetus. MIMS

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