What is the problem with acetaminophen (Tylenol)?
To be “associated”, when taken during pregnancy, with an increased risk of neurodevelopmental disorders such as autism and attention deficit hyperactivity disorder (ADHD). On September 22, the US drug regulator, the FDA, sent a “letter to physicians” making this assertion, citing two studies from 2019 and 2020. The FDA added, however, that no “causal link” had been established with acetaminophen during pregnancy, that acetaminophen is the only over-the-counter medication approved to treat fever during pregnancy, and that fever “poses a risk” to the fetus.
At a press conference the same day, President Donald Trump and his Secretary of Health, Robert F. Kennedy Jr., went further in their denunciation of acetaminophen, citing a study published last summer in which one of the co-authors was an advisory witness in a lawsuit linking acetaminophen to autism. ” Hold fast ” (tough it out), President Trump advised pregnant women tempted to take acetaminophen.
In the wake of this announcement, an anti-vaccination group, Informed Consent Action Network (ICAN), asked the FDA to require acetaminophen manufacturers to add to their labels a mention of this association with neurodevelopmental disorders such as autism, without mentioning the risk of fever.
The FDA indicated on September 22 that there would be a change to the labels, without further details.
The maker of Tylenol this week opposed ICAN’s request because it is “not supported by scientific evidence.”
Who is right?
A much more robust study was published in 2024 and ruled out any association between acetaminophen and autism, according to Éric Fombonne, an autism specialist who long taught at McGill University and is now at the University of Oregon. This 2024 study considered siblings of children whose mothers took acetaminophen during pregnancy, which ruled out the association with neurodevelopmental disorders. It was therefore a common genetic risk leading to neurodevelopmental risk and pain and fever during pregnancy, leading to the use of acetaminophen.
A Japanese study also including siblings more recently came to the same conclusion as the 2024 study, as did a Montreal study published last summer, notes Dr.r Fombonne. Note, the Montreal study ruled out an association between acetaminophen and autism, but observed a “weak” association between acetaminophen and ADHD.
Does an FDA-like warning typically lead to warnings on drug packages?
It all depends on the risks and benefits, says Robert Platt, director of the School of Population and Global Health at McGill University. “There is a calculation to be made between limiting exposure to medications during pregnancy, if there is a possible association with disorders, and the risks of not taking these medications. »
The Canadian and American Societies of Obstetrics and Gynecology, for example, are concerned that pregnant women may not treat their fever and expose their fetuses to well-established neurodevelopmental risks, if the warnings requested by ICAN are accepted.
“Fever during the first trimester increases the risk of neurodevelopmental disorders,” says Dr.r Fombonne.
Has Health Canada also requested such a warning?
The Press asked Health Canada if it has received a request similar to ICAN’s petition.
In an unsigned email response, Health Canada did not respond to the question, only indicating that “there is no evidence to establish that taking acetaminophen as directed during pregnancy causes autism or other neurodevelopmental disorders.”
Lili Plourde, general director of the Quebec Autism Federation, believes that it is not desirable to add to acetaminophen labels a sentence indicating that its use during pregnancy could be “associated” with a neurodevelopmental risk for the baby, to prevent pregnant women from not treating their fever.
What other actions has the Trump administration taken on autism?
Robert F. Kennedy Jr. last spring hired David Geier, a well-known anti-vaccine activist, to lead a study on the autism risks of vaccines. Mr. Geier began such a study 20 years ago using a federal database, but was stripped of access to that database because he lied about his intentions. In September, the medical news site Statnews reported that those responsible for this federal vaccine database were still preventing Mr. Geier from accessing it.
The Dr Fombonne is not reassured. “If (Robert F. Kennedy Jr.) decided that Geier would do this study, he’s going to eventually have access to the database. We are talking about a person, Geier, who has already been convicted of illegal practice of medicine because of his statements about vaccines and autism. »
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- 3.2%
- Proportion of 8-year-olds diagnosed with autism in the United States in 2022
Source: Centers for Disease Control and Prevention (CDC)
