Does Tylenol Use during Pregnancy Cause Autism? What the Research Shows
The Trump administration today plans to link the increase in autism spectrum disorder rates to the use of Tylenol (a brand of acetaminophen) during pregnancy, according to reports by Wall Street Journal and the Washington Post. President Donald Trump presented an overview of the announcement on Sunday, saying that during a memorial for the late Charlie Kirk, “I think we found an answer to autism.” A press conference will take place this afternoon.
This story will be updated throughout the day.
There is no simple response to the cause of autism, more than 50 years of scientific research showed. It is a complex neurodevelopmental condition which stems from a constellation of genetic factors and environmental influences.
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In addition, evidence connecting the use of tylenol during pregnancy to possible autism diagnoses in children are low. “The evidence [from a handful of studies] was really mixed and the effects were really small, “said David Mandell, professor of psychiatry studying autism at the University of Pennsylvania, in an interview with American scientist Earlier this month.
Acetaminophen is one of the rare analgesics deemed safe to take during pregnancy, in consultation with doctors, according to the American College of Obstetricians and Gynecologists (ACOG). “Despite recent untreated allegations, there is no clear evidence linking prudent use to problems with fetal development. ACOG guidelines remain the same. When pain relief is necessary during pregnancy, acetaminophen should be used in moderation and after consulting your doctor,” the professional body wrote in a statement on September 5.
Here is what we know about tylenol and causes of autism.
What causes autism?
The majority of autism cases can be linked to genetic causes. But this DNA plan does not determine everything: as a fertilized human egg turns into embryo and then into fetus, environmental factors can influence the way in which these genetic instructions are carried out.
Certain non -freezic factors have repeatedly linked to a high risk of developing an autism spectrum disorder. The most well established is parental age: the more the parents of a person are old at the time of the design of this person, the more likely it is that this person is diagnosed with autism. (But even this effect can link to genetics because, as people age, they accumulate more genetic mutations that they could transmit to their offspring.)
It has been shown that other non -freezic factors, such as birth or birth premature by a cesarean, maternal diabetes and exposure to air pollution or certain utero antisizure drugs increase the risk of a person in certain studies. But these results cannot establish that these factors have caused an increased risk of autism, but they sometimes occur together. Indeed, it is generally impossible, impractical or contrary to the ethics of carrying out randomized trials on pregnant populations.
Find out more: Autism has no unique cause. Here’s how we know
What shows the evidence of Tylenol and autism?
A handful of studies in the United States and Europe have found a modest increase in the risk of autism among the offspring of people who took acetaminophen during pregnancy. The largest recent study, however, has found no effect. The 2024 analysis examined nearly 2.5 million people born in Sweden between 1995 and 2019. The researchers found a very low increase in the prevalence of autism among the offspring of people who took acetaminophen while they were pregnant compared to the offspring of those who did not – the risk was 0.09 higher percentage point. This high risk disappeared when the researchers simply examined the cases of peer brothers in which one person has taken acetaminophen during a pregnancy and not the other. This suggests that what was initially like a high risk of autism from acetaminophen during pregnancy can be the result of other risk factors.
The most obvious factor that could influence these results is the reason why people take tylenol during pregnancy in the first place. The drug is used to relieve pain and reduce fever. “In any of these studies, I don’t see where [the researchers] were able to separate the effects of the prenatal infection of the use of acetaminophen, ”explains Mandell.
This means that the fever or underlying infections of Tylenol was used to treat could be part of what has led to the increased risk of autism that has been shown in certain studies. If a pregnant person is hospitalized for an infection, the probability that their child develops autism increases by around 30%, a study of more than two million people found.
“We believe that independent and solid science clearly shows that the taking of acetaminophen does not cause autism. We are strongly disagreed with any suggestion otherwise and we are deeply concerned about the health risk that this poses for the expectations of mothers,” said a spokesperson for Kenvue, the manufacturer of Tylenol, in a press release sent to American scientific.
Potential treatment
The Trump administration also plans to connect autism to low folate levels, or vitamin B9, during pregnancy.
“We know that Folate deficiency during pregnancy causes neural tube defects or increases the risk of neuronal tube defects,” explains Mandell, referring to the structure of an embryo that ends up developing in the brain and spinal cord. “It is also believed that it could also lead to a learning disorder, a delay in development, including autism.” This idea has led many doctors and parents of autistic people to try to treat the disease with B vitamins, including leucuvorine, also known as folinic acid.
“The question of whether fetal deficiency affects fetal development is a very different question from that” can increase the symptoms of the folate after swimming of autism? ” “Said Mandell. A few small controlled trials randomized of folinic acid such as treatment of autism spectrum disorder have been conducted, and they showed small effects.
“Should we lead a large-scale randomized trial of folinic acid and autism?” Absolutely. And the reason we should do it is because science must catch up here [because] It is already prescribed, ”continues Mandell.
Increase rate
Autism rates have increased, which Robert F. Kennedy, Jr., often calls an “epidemic”. However, the causes of this elevation are relatively well known. As our understanding of autism has improved, the diagnostic criteria were widened and a major change occurred in 2013 when autism and several other conditions were combined in a single continuous spectrum disorder in the Diagnostic and statistical manual of mental disorders. Improvement of screening alerts clinicians in more cases in children, and adults whose autism was missed when they were younger in search of diagnostics. In addition, a better understanding of autism has enabled better diagnoses of people who, in previous decades, may have received other diagnoses such as “intellectual disability”.
Find out more: The real reason why autism rates increase
In April, Kennedy said that his Ministry of Health and Social Services would find the cause of autism by September. But science often does not occur on such short deadlines, experts say. The administration’s decision to highlight acetaminophen and the Folate does not come from new evidence but rather from previously published results which are mixed and indicate the need for more research.
“The idea that [the administration] Highlighting two things that have such small, controversial and weak evidence are really worrying, “says Mandell -” especially when we know so much about autism genetics, and we know so much on other environmental factors that increase the risk of autism. »»
“A press release that talks about a potential association will cause a lot of fear,” said Debra Houry, a former chief of Centers for Disease Control and Prevention, during a press call that this morning, organized by the Defend America Action group. Houry participated alongside other former CDC leaders who had resigned this month. “If there is not science to safeguard it, we will see changes in practice, worried moms, all kinds of things, and it is not appropriate. You must be anchored in the science of golden standards,” she said.
Additional report by Lauren Young.
