Many women and doctors dismiss Trump’s Tylenol claim as more research suggests no autism link

By Jacqueline Howard, CNN

(CNN) — When President Donald Trump claimed last year that taking Tylenol during pregnancy can be linked with an increased risk of autism, ob-gyn Dr. Nathaniel DeNicola’s office had an influx of questions and confusion – but only for a few days.

“Then, after a week, it had kind of gone away as a hot-button topic,” said DeNicola, based in Newport Beach, California, who helped author the American College of Obstetricians and Gynecologists’ guidance on the use of acetaminophen in pregnancy.

At the time, the scientific medical community “was so prompt in its response and so definitive in its assertion of the utility and safety of Tylenol during pregnancy as needed, I don’t think there was any lasting confusion, at least from those who listen to the medical experts,” DeNicola said.

“Patients, I think correctly, are going to their doctors,” he added. “The public seems to have taken the direction from the experts, that they trust their voice on this.”

Chicago-based maternal-fetal medicine physician Dr. Lynn Yee said that fewer of her patients seem worried about Tylenol now than in the fall.

“In September, October, November, there was quite a bit of public concern and attention on this topic, and now, in January, I feel like things are changing and that I have fewer patients asking me about Tylenol or acetaminophen,” said Yee, chief of maternal-fetal medicine in the Department of Obstetrics and Gynecology at the Northwestern University Feinberg School of Medicine.

“I’m really proud of our professional organizations like American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine. They’ve done a lot of messaging around the safety of acetaminophen and ‘talk to your doctor,’” she said. “All these trusted organizations have been doing a commendable job of getting the right messages out there, and maybe it’s working.”

Experts stress that autism has many potential causes – including genetics, advanced parental age, and prenatal exposure to air pollution or certain pesticides – and that the science linking it to acetaminophen remains far from settled.

In guidance released after Trump’s claims in September, ACOG reaffirmed that “acetaminophen remains the analgesic and antipyretic of choice during pregnancy. Judicious use at the lowest effective dose for the shortest necessary duration, in consultation with an obstetrician–gynecologist or other obstetric care professional, remains consistent with best practice.”

Acetaminophen, also known as paracetamol and sold under the brand name Tylenol, is widely considered the only safe over-the-counter option for treating pain or fever during pregnancy. Other common medications, such as ibuprofen or regular-dose aspirin, can raise the risk of serious complications during pregnancy.

In many cases, doctors may recommend Tylenol to treat pain or fever. Leaving a fever untreated can be dangerous for both the fetus and the mother, experts warn, increasing the risk of miscarriage, birth defects, high blood pressure and neurodevelopmental disorders.

“Untreated fevers can have short- and long-term impacts on fetal neurodevelopment,” Yee said. “It’s really important to treat your fever, because we know that untreated fever during pregnancy is unhealthy for both the mom and the baby. … And we don’t have better, safe alternatives for reducing fevers during pregnancy.”

It’s estimated that about 65% of pregnant women use acetaminophen at some point during pregnancy.

A medical issue turns political

The White House released a fact sheet in September referencing various studies suggesting that acetaminophen use during pregnancy, especially late in pregnancy, may cause long-term neurological effects in children, such as autism or ADHD.

At the time, the US Food and Drug Administration issued a letter to physicians stating that “clinicians should consider minimizing the use of acetaminophen during pregnancy for routine low-grade fevers” and that in recent years, “evidence has accumulated suggesting that the use of acetaminophen by pregnant women may be associated with an increased risk of neurological conditions such as autism and ADHD in children.”

One of the papers that the Trump administration referenced was an analysis of 46 previous studies. That review, published in August in the journal BMC Environmental Health, found evidence of a link between acetaminophen exposure during pregnancy and an increased incidence of neurodevelopmental disorders.

“This association is strongest when acetaminophen is taken for four weeks or longer,” the paper’s senior author, Dr. Andrea Baccarelli, dean of the faculty at the Harvard T.H. Chan School of Public Health and professor of environmental health, said in a statement in September.

Baccarelli said he had discussed his research with US Health and Human Services Secretary Robert F. Kennedy Jr. in the weeks leading up to the White House’s announcement.

“At the same time, as the only approved medication for pain and fever reduction during pregnancy, acetaminophen remains an important tool for pregnant patients and their physicians. High fever can pose risks to both the mother and the fetus, including neural tube defects and preterm birth,” he said.

“After assessing the evidence, my colleagues and I recommended a balanced approach based on the precautionary principle: Patients who need fever or pain reduction during pregnancy should take the lowest effective dose of acetaminophen, for the shortest possible duration, after consultation with their physician about their individual risk-benefit calculation.”

Now, new research is adding to the discourse.

‘Reassurance rather than alarm’

A paper published Friday found no indication that children born to mothers who used acetaminophen during pregnancy have an increased likelihood of autism.

The research, published in The Lancet Obstetrics, Gynaecology & Women’s Health, reviewed 43 published studies on prenatal acetaminophen exposure and potential links with child neurodevelopment, including data on more than 300,000 pregnancies. Of those studies, 17 were included in a meta-analysis.

“We looked at a number of outcomes, including autism, ADHD and intellectual disability,” lead author Dr. Asma Khalil, consultant obstetrician and fetal medicine specialist at St George’s Hospital in London, said in a news briefing.

The researchers found no evidence that acetaminophen use during pregnancy increases the risk of autism, attention-deficit/hyperactivity disorder or intellectual disability among children.

The US Department of Health and Human Services said in a statement that the new paper does not resolve questions around Tylenol’s potential risks and excludes the majority of studies on the topic.

In response, Khalil said in an email that the review paper “does not exclude evidence” but rather systematically evaluated all studies and gave greater weight to the ones “best able to address bias and confounding” factors.

“While we acknowledge that even small effects can matter at a population level, public health guidance must be grounded in the strongest available evidence, not in signals driven by bias or confounding by indication,” she wrote. “This review provides reassurance rather than alarm, and it supports current clinical guidance that paracetamol remains an appropriate first-line treatment for pain and fever in pregnancy when used as recommended.”

Some of the studies in the new analysis included data on siblings, in which the mother may have used acetaminophen while pregnant with one child but not the other.

“Sibling-comparison meta-analyses represent the primary evidence, since they account for shared familial and genetic factors,” the researchers wrote in their paper.

Prioritizing these sibling studies was a strength of the new research, Dr. Steven Kapp, a senior lecturer in psychology at the University of Portsmouth who was not involved in the new study, said in a statement distributed by the UK-based Science Media Centre.

“Its scientific rigour included accounting for cofounders such as having a sibling with the condition, as these neurodivergences run in families. Parents of disabled children might be more likely to take paracetamol because of pains related to parenting stress or their own chronic conditions,” Kapp said.

“The sibling control in these studies shows that the medication does not cause their child’s disability. As a neurodivergent researcher and advocate, I think an implication is that society needs to stop going down rabbit holes of seeking false prevention of developmental disabilities,” he said. “Instead, we should focus more on making the world a better place for disabled people.”

DeNicola, who was not involved in the research, also praised the work but added that “there have only been to date three sibling studies,” as indicated in the paper.

“So, do three studies answer any given question? That’s a fair limitation. You always like to have more information,” he said. “But considering that all three studies say the exact same thing, done with superior methods, it at least provides the reassurance to date that we should be using the therapeutic benefit of Tylenol without any unfounded risk.”

In their paper in August, Baccarelli and his colleagues wrote that “sibling comparison analyses have significant limitations that affect their interpretation” and that “while sibling comparison studies eliminate the impact of shared family factors that operate as confounders, they also eliminate potential mediators that are shared in families that interact with acetaminophen, potentially introducing bias.”

Some potential mediators that may cluster within families, they said, include disruptions to the body’s hormone system or increased oxidative stress.

But Khalil described sibling comparisons as among the “best” study designs to account for shared factors that may influence autism risk.

“This is the best, probably, design to help to take into account of shared genetic factors, or shared family environment – that these two children are exposed to the same environment, or long-term parenting characteristics, socio-economic backgrounds, education backgrounds – and many of the other studies that were included or published in literature did not fully account for that,” she said.

Khalil said the new research was conducted because she and her colleagues came across pregnant women who were worried about the safety of acetaminophen due to what Trump said last year.

That fear among patients at the time was “certainly my experience,” Khalil said.

National and international medical groups “responded quite quickly with issuing statements trying to reassure pregnant women,” she recalled. “And it made the message clear to pregnant women that it’s safe to use paracetamol when needed in the right dose for the right duration.”

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