The White House recently issued a press release referencing research papers to support assertions that acetaminophen use during pregnancy causes autism, but medical experts describe the evidence as “limited” and “inconclusive”.
Statement Presents Impression of Extra Evidence
According to a surgeon and senior fellow, the official statement creates the appearance of extra evidence by linking to the identical research multiple times.
For instance, a recent review paper by Mount Sinai and Harvard is made to look like two separate studies, and a Johns Hopkins research is also linked twice.
It’s claimed a research from Harvard found the identical result as the Johns Hopkins research and the Mount Sinai study. It creates the impression that identical findings have been achieved in one study after another, all from very prestigious centers,” Singer said.
Association vs Causation: Key Distinction
A physician from Stanford expressed concern that the statement is deeply troubling”, because it “presents association as causation.
There is a much higher bar for proving causation than association. Proving causation would mean demonstrating that stopping use to Tylenol would decrease the number of autism cases.
As an illustration, increased ice cream purchases might be associated with heat-related illness, only because both occur in the summer, but banning the sale of ice cream would not reduce the heat stroke cases.
Studies Acknowledge Shortcomings
Not one paper cited by the press release claim to have proven cause. In fact, all of them admit they cannot conclusively prove causation, although some use more cautious wording than others.
One way to rapidly identify the extent of research assertions is to search for important phrases like “causal”, “causation”, “correlation”, “constraints”, “caution”, and “additional research”.
Physiological Processes Claim Falls Apart
Upon examining the research, additional claims in the press release begin to unravel, experts said.
For example, the statement claims that researchers have suggested biological mechanisms connecting acetaminophen use during pregnancy to altered brain development.
However the research cited to illustrate a physiological process fails to provide one. Instead, the researchers state: The processes behind the links are not understood.”
Omitted Research and Confounding Factors
Another way to fact check the research assertions is to look at what studies are omitted.
As an instance, the press release left out a Swedish study published in 2024 that followed nearly two and a half million births and used sibling controls.
Singer explained that the association vanishes when comparing siblings, who have many more genetic and environmental similarities than comparison groups in different research.
“This suggests that links seen in different studies may have been attributable to confounding,” the authors noted.
Habit of Using Poor Research
Singer and Scott concur that the Tylenol claims are reminiscent of anti-vaccine rhetoric.
Scott said that it follows a trend of exploiting really weak evidence based on really poor quality studies.
“It’s all part of a pattern of exploiting really weak evidence that’s based on really poor quality studies,” Scott said.
In summary, physicians caution that the evidence linking Tylenol to autism is not definitive and urge more studies before reaching definite judgments.
