Acetaminophen-autism link research gets boost from Texas Tylenol liability fraud lawsuit

When Missouri Attorney General Andrew Bailey sued Planned Parenthood this summer for allegedly misrepresenting the safety of abortion pills for pregnant women, the Republican cited the group's claim that "medication abortion" is safer than even Tylenol.

Both might want to reconsider the comparison in light of new federal and red-state skepticism of acetaminophen, the active ingredient in brand-name Tylenol, taken during pregnancy.

Taking a page from Bailey's playbook, Texas GOP Attorney General Ken Paxton sued Johnson & Johnson and its 3-year-old spinoff Kenvue, which now owns Tylenol, for promoting the drug "as the only safe painkiller for pregnant women," despite allegedly knowing for "decades" that acetaminophen is "dangerous to unborn children and young children."

The Republican connected the spinoff, which transferred Tylenol-related liabilities to Kenvue, to J&J seeing a "reckoning on the horizon" in the face of "mounting scientific evidence link[ing] prenatal and early-childhood exposure to acetaminophen" with autism spectrum disorder and attention-deficit hyperactivity disorder, violating Texas law on "fraudulent transfer."

A Kenvue spokesperson claimed acetaminophen is the "safest pain reliever option for pregnant women as needed throughout their entire pregnancy," and not taking it could risk pregnancies via "high fevers and pain."

The company did not acknowledge its own recommendations in 2017 and 2019 not to take Tylenol at all during pregnancy because the drug wasn't tested in that setting.

Paxton's legal pugilism is a dramatic escalation of last month's advice to pregnant women, by President Trump and the Department of Health and Human Services, to avoid Tylenol and acetaminophen, a warning that Sen. Ron Johnson, R-Wis., characterized as "just cautionary" and Rep. Eric Burlison, R-Mo., as "do your homework."

J&J is already reeling from a nearly billion-dollar jury verdict earlier this month for the family of an elderly woman, that blamed her death from mesothelioma on talcum powder-based products, phased out in 2020, that allegedly contained asbestos fibers connected to the rare cancer. 

A spokesperson blamed the "egregious and unconstitutional" jury award, all but $16 million in punitive damages, on "junk science." The Supreme Court has suggested punitive damages more than nine times higher than compensatory are unconstitutional, and a conservative activist is challenging Washington state's similarly skewed ratio against him.

Reuters reported J&J is facing lawsuits by 67,000 plaintiffs who took its talc-based products, the vast majority concerning ovarian cancer, and suffered several large verdicts in mesothelioma cases in the past year while winning a few or getting new trials.

"The transfer of liabilities from Johnson & Johnson to Kenvue without also transferring sufficient assets to cover the liabilities is something Johnson & Johnson does frequently," Paxton's lawsuit says. "It recently tried this tactic three times after it faced large verdicts because its talc powder caused cancer in women. Each time, its efforts were rebuffed."

Prominent medical school: 'higher-quality studies are more likely to show a link'

The AG's lawsuit invokes "at least twenty-six epidemiological studies" that have shown "positive associations between prenatal use of acetaminophen and ASD and/or ADHD." All eight that looked for a "dose-response relationship" between the drug and the conditions – two for ASD, six for ADHD – found such a relationship, he said.

The most prominent appears to be a 2020 study published in the Journal of the American Medical Association Psychiatry, which overcame the "maternal self-report" bias in earlier research on acetaminophen-ASD-ADHD associations by measuring "cord acetaminophen metabolites" in "archived cord plasma samples collected at birth."

Tracking nearly 1,000 "mother-infant dyads" from 1998 through 2018, about a quarter of children had ADHD only, 7% ASD only, 4% with both, 31% with other developmental disorders and 33% "neurotypical," according to the researchers from HHS and medical schools in Baltimore and Boston.

"Cord biomarkers of fetal exposure to acetaminophen were associated with significantly increased risk of childhood ADHD and ASD in a dose-response fashion," they wrote, reinforcing previous studies of acetaminophen exposure and childhood neurodevelopmental risk and warranting "further investigation."

Paxton also cited a 2021 "call for precautionary action" signed by "91 scientists, clinicians and public health professionals" worldwide, including from Yale, the University of Massachusetts and New York's Mount Sinai, that cites "increasing experimental and epidemiological research suggests that prenatal exposure … might alter fetal development."

While acetaminophen "is an important medication and alternatives for treatment of high fever and severe pain are limited," the signatories recommend cautioning newly pregnant women to forgo it "unless its use is medically indicated," confirm with a physician or pharmacist, and "minimize exposure by using the lowest effective dose for the shortest possible time."

A month before the Trump administration's warnings, Mount Sinai's Icahn School of Medicine touted its researchers' new federally funded study in BMC Environmental Health on acetaminophen, ASD and ADHD, "the first to apply the rigorous Navigation Guide methodology to systematically evaluate the rigor and quality of the scientific literature."

Analyzing 46 studies with data from more than 100,000 participants globally, the researchers found "higher-quality studies are more likely to show a link between prenatal acetaminophen exposure and increased risks of autism and ADHD," said Assistant Professor of Population Health Science and Policy Diddier Prada.

"Given the widespread use of this medication, even a small increase in risk could have major public health implications," Prada also said. 

"Acetaminophen is known to cross the placental barrier and may trigger oxidative stress, disrupt hormones, and cause epigenetic changes that interfere with fetal brain development," the Icahn School press release said, while cautioning the study "does not show that acetaminophen directly causes neurodevelopmental disorders."

Much like pediatric neurologist Richard Frye cautioned against reading too much into his research on leucovorin as an off-label autism treatment after the Trump administration rushed its approval, the Yale School of Public Health tried to box in its own "precautionary" letter signatory after the Trump administration's warnings.

Associate Professor of Epidemiology Zeyan Liew "says that there is no proven causal relationship between acetaminophen use and autism," the school paraphrased Liew for its "4 essential questions" feature Sept. 23.

"Several large observational studies have reported 'associations'" but "experts emphasize that these studies are not conclusive," the school said. When it asked Liew if acetaminophen use in pregnancy causes autism, he responded they don't know "yet for sure" but largely reiterated the precautionary letter's tradeoff language.

Increase in diagnoses from 'shifts in diagnostic practice and societal incentives'

A related scientific debate is playing out over how to explain the spike in ASD and ADHD diagnoses in recent decades: genuine, a diagnostic figment or something in between.

A Swedish team of psychologists shared their findings from a two-year reassessment of diagnoses, a collaboration among regional public healthcare provider Region Skåne, Lund University and the University of Gothenburg, at last month's Preventing Overdiagnosis conference at the University of Oxford.

Team lead Sebastian Lundström said the increase in diagnoses in the region "appears to reflect shifts in diagnostic practice and societal incentives rather than an actual increase in underlying neurodevelopmental traits." 

The 74 participants who sought reassessment often described the process "as opaque and adult-driven, leaving little room for the child’s own perspective."

Lundström warned there was "no clear demarcation between individuals with and without" an ASD or ADHD diagnosis, which represent the "extreme end of a distribution of traits." 

A British Columbia school study credited at least a third of the ASD increase to "diagnostic substitution across psychiatric disorders," while an Australian study found up to 20% of clinicians falsely diagnosed ASD "to grant access to societal services," he noted.

His own team found, "all else being equal, having relatively mild autistic and/or ADHD traits today seems to be more impairing in terms of mental health and functioning than it was ten or twenty years ago, although the reasons for this change remain unknown."

The idea that autism can be substantially overcome, not just mourned or embraced as a fixed identity, is getting renewed attention thanks to a memoir by NewsNation chief Washington anchor Leland Vittert, which credits his father's 15-year full-time effort with helping Vittert "adapt to the world—and thrive in it."