Appeals court revives 500-plus lawsuits alleging Tylenol-autism link

Major medical groups continue to recommend acetaminophen in pregnancy

The 2nd U.S. Circuit Court of Appeals in Manhattan on Monday revived more than 500 private lawsuits against Tylenol maker Kenvue over the painkiller’s alleged link to autism and attention deficit hyperactivity disorder when taken during pregnancy, allowing the cases to proceed after a lower court had shut them down before trial.

The appeals court ruled that a federal trial judge had erred by excluding the plaintiffs’ expert medical witnesses, whose testimony was expected to support a connection between prenatal Tylenol exposure and neurodevelopmental disorders. The decision sends the cases back to the lower court for further proceedings.

At the trial level, the judge had excluded expert reports — including one by Dr. Andrea Baccarelli, dean of Harvard University’s public health school — after concluding that the reports cherry-picked results and were unreliable. That ruling had effectively gutted the plaintiffs’ case before trial.

Researchers have studied a potential relationship between acetaminophen and neurodevelopmental disorders for decades without proving a causal link. Major medical groups have long recommended acetaminophen, sold in the United States as Tylenol, as the preferred pain reliever for pregnant women, according to the Wall Street Journal.

The question drew heightened public attention after President Donald Trump and top U.S. health officials in September suggested a link between Tylenol and autism, Insurance Journal reported. The publication added that there is no firm scientific evidence of such a link.

A review of 43 studies published in January by The Lancet’s Obstetrics, Gynecology & Women’s Health journal concluded that taking acetaminophen during pregnancy does not increase the risk of autism, ADHD or intellectual disabilities. A separate Lancet study reported in March found that Tylenol orders for pregnant emergency department patients were 10 percent below predicted levels after a White House briefing by Trump on the alleged link.

Kenvue, the consumer-health company that manufactures Tylenol, was spun off from Johnson & Johnson. Kimberly-Clark has agreed to acquire Kenvue for more than $40 billion in a transaction announced while the litigation remains pending.

The 2nd Circuit’s decision did not address the underlying scientific question of whether Tylenol causes autism or ADHD. The court determined only that the trial judge had applied the wrong standard in screening the experts’ testimony. The cases now return to the lower court for further proceedings.