In a press convention this afternoon, the Trump administration linked rising charges of autism spectrum dysfunction to the usage of Tylenol (a model title of acetaminophen) throughout being pregnant. “Don’t take it if you happen to’re pregnant. Don’t take Tylenol,” President Trump mentioned, repeatedly emphasizing that pregnant individuals with fever ought to “robust it out” as a lot as they’ll, regardless of proof that uncontrolled fever and infections throughout being pregnant can themselves improve threat of autism.
This story can be up to date because it develops.
There is no such thing as a easy reply to what causes autism, greater than 50 years of scientific analysis has proven. It’s a complicated neurodevelopmental situation that arises from a constellation of genetic elements and environmental influences.
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What’s extra, the proof linking the usage of Tylenol throughout being pregnant to eventual autism diagnoses in youngsters is weak. “The proof [from a handful of studies] was actually blended, and the results had been actually small,” mentioned David Mandell, a professor of psychiatry finding out autism on the College of Pennsylvania, in an interview with Scientific American earlier this month.
Acetaminophen is without doubt one of the few ache relievers deemed protected to take throughout being pregnant, in session with docs, in keeping with the American Faculty of Obstetricians and Gynecologists (ACOG). “At the moment’s announcement by HHS isn’t backed by the complete physique of scientific proof and dangerously simplifies the numerous and sophisticated causes of neurologic challenges in youngsters. It’s extremely unsettling that our federal well being businesses are prepared to make an announcement that may have an effect on the well being and well-being of tens of millions of individuals with out the backing of dependable information,” wrote the skilled physique in an announcement despatched on Monday to Scientific American.
Right here’s what we learn about Tylenol and the causes of autism.
What causes autism?
Nearly all of autism circumstances will be linked to genetic causes. However that DNA blueprint doesn’t decide every thing: as a fertilized human egg turns into an embryo after which right into a fetus, environmental elements can affect how these genetic directions are carried out.
Some nongenetic elements have been repeatedly linked to an elevated threat of creating autism spectrum dysfunction. Essentially the most well-established one is parental age: the older an individual’s mother and father are on the time of that particular person’s conception, the extra doubtless it’s that that individual can be recognized with autism. (However even this impact may tie again to genetics as a result of, as individuals age, they accumulate extra genetic mutations that they could move on to their offspring.)
Different nongenetic elements, resembling untimely start or start by cesarean part, maternal diabetes and publicity to air air pollution or sure antiseizure medication in utero have been proven to extend an individual’s threat of autism in some research. However these outcomes can’t set up that these elements brought about the elevated threat of autism, solely that they generally happen collectively. That is as a result of it’s often unimaginable, impractical or unethical to run randomized trials on pregnant populations.
READ MORE: Autism Has No Single Trigger. Right here’s How We Know
What does the proof for Tylenol and autism present?
A handful of research from the U.S. and Europe have discovered modest will increase in autism threat among the many offspring of people that took acetaminophen whereas pregnant. The largest latest examine, nonetheless, discovered no impact. The 2024 evaluation checked out practically 2.5 million individuals born in Sweden between 1995 and 2019. The researchers discovered a really small improve within the prevalence of autism among the many progeny of people that took acetaminophen whereas they had been pregnant in contrast with the offspring of those that didn’t—the chance was 0.09 proportion factors larger. This elevated threat disappeared when researchers simply checked out sibling-pair circumstances during which an individual took acetaminophen throughout one being pregnant and never the opposite, nonetheless. This implies that what initially appeared like an elevated threat of autism from acetaminophen throughout being pregnant could have been a results of different threat elements.
The obvious issue that might be influencing these outcomes is the rationale individuals take Tylenol throughout being pregnant within the first place. The drug is used to alleviate ache and to scale back fever. “In none of those research do I see the place [the researchers] had been capable of separate out the results of prenatal an infection from the acetaminophen use,” Mandell says.
Which means that the fever or underlying infections Tylenol was used to deal with might be a part of what drove the elevated threat of autism that was proven in some research. If a pregnant individual is hospitalized with an an infection, the chance that their youngster will develop autism will increase by roughly 30 %, a examine of greater than two million individuals discovered.
“In additional than 20 years of analysis on the usage of acetaminophen in being pregnant, not a single respected examine has efficiently concluded that the usage of acetaminophen in any trimester of being pregnant causes neurodevelopmental issues in youngsters,” wrote ACOG in its assertion to Scientific American.
“We consider impartial, sound science clearly reveals that taking acetaminophen doesn’t trigger autism. We strongly disagree with any suggestion in any other case and are deeply involved with the well being threat this poses for anticipating moms,” a spokesperson of Kenvue, Tylenol’s producer, mentioned in a separate assertion despatched to Scientific American.
READ MORE: Tylenol is Common and Secure, But No one Is aware of The way it Works
A Potential Remedy
The Trump administration additionally linked autism to low ranges of folate, or vitamin B9, throughout being pregnant.
“We all know that folate deficiency throughout being pregnant ends in neural tube defects or will increase threat for neural tube defects,” says Mandell, referring to the construction in an embryo that finally develops into the mind and spinal twine. “There’s some thought that it might additionally end in studying incapacity, developmental delay—together with autism.” This concept has led many docs and fogeys of individuals with autism to attempt treating the situation with B nutritional vitamins, together with leucovorin, also called folinic acid.
“Whether or not folate deficiency impacts fetal growth is a really totally different query than ‘Can rising folate postnatally scale back autism signs?’” Mandell says. A couple of small, randomized managed trials of folinic acid as a remedy for autism spectrum dysfunction have been performed, they usually have proven small results.
“Ought to we run a large-scale randomized trial of folinic acid and autism? Completely. And the rationale we must always do it’s as a result of the science must meet up with follow right here [because] it’s already being prescribed,” Mandell continues.
Rising charges
Autism charges have been rising, one thing that Robert F. Kennedy, Jr., regularly refers to as an “epidemic.” The causes of this rise are comparatively well-known, nonetheless. As our understanding of autism has improved, the diagnostic standards have broadened, and a serious change occurred in 2013 when autism and several other different circumstances had been mixed into one steady spectrum dysfunction within the Diagnostic and Statistical Handbook of Psychological Problems. Improved screening is alerting clinicians to extra circumstances in youngsters, and adults whose autism was missed after they had been youthful are searching for diagnoses. Moreover, improved understanding of autism has allowed for higher diagnoses of people that, in prior a long time, could have obtained different diagnoses resembling “mental incapacity.”
READ MORE: The Actual Motive Autism Charges Are Rising
In April Kennedy mentioned that his Division of Well being and Human Companies would discover the reason for autism by September. However science typically doesn’t occur on such brief timelines, specialists say. The administration’s resolution to focus on acetaminophen and folate doesn’t come from new proof however quite from beforehand revealed outcomes which might be blended and level to the necessity for extra analysis.
“The concept [the administration] would spotlight two issues which have such small, controversial and weak proof is de facto regarding,” Mandell says—“particularly once we know a lot concerning the genetics of autism, and we all know a lot about different environmental elements that improve the chance for autism.”
“A press assertion that talks a few potential affiliation will trigger a lot of worry,” mentioned Debra Houry, former chief medical officer of the Facilities for Illness Management and Prevention, in a press name this morning hosted by the group Defend America Motion. Houry participated alongside different former CDC leaders who had resigned this month. “If there’s not the science to again it up, we’ll see follow modifications, apprehensive mothers, all types of issues, and that’s not acceptable. You must be grounded in gold normal science,” she mentioned.
Extra reporting by Lauren Younger.
Editor’s Word (9/22/25): This text was up to date after posting to incorporate President Trump’s statements from the press convention. Extra statements from Kenvue and the American Faculty of Obstetricians and Gynecologists had been additionally included after posting.
