Health Secretary Robert F. Kennedy’s claims of a link between Tylenol use by pregnant women and autism could breathe life into scores of lawsuits against its maker — including a class action that is scheduled for  a hearing next month.

The Trump administration says there is a link between acetaminophen, the active ingredient in Tylenol, and autism. Despite decades of doctors recommending it as a fever reducer during pregnancy, Mr. Kennedy is advising against pregnant women using it. President Trump is going a step further — saying pregnant women absolutely should not use it. Mr. Trump even suggests that children should not use it.

Acetaminophen has long been considered the safest over-the-counter pain medication for pregnant women but a series of lawsuits allege Kenvue, the drug’s maker, failed to issue a warning that using the drug during pregnancy could cause the child to develop autism or ADHD.

The U.S. Court of Appeals for the Second Circuit is currently reviewing a class action suit that bundles about 500 cases together. Oral arguments are scheduled for October 6.

The appellate court is expected to address scientific and evidentiary issues that will determine whether the claims move forward in federal court or are dismissed. It is unclear if the administration’s new stance will influence the court. It could depend on whether the court is willing to reconsider experts who were not viewed as credible at the lower court.

The deputy director at the Consumer Choice Center, Yaël Ossowski, says a district judge threw out the case because the expert testimonies used by the plaintiffs were determined to lean on dubious studies to make their case.

“It can’t be forgotten that one of the expert witnesses that was in that trial, who the judge lambasted, is essentially the Harvard researcher who’s being cited in most of these Tylenol warnings now by the government,” Mr. Ossowski tells the New York Sun. “So, the same individual who was effectively called out for improper science testimony in this trial is the one that’s being relied upon for this evidence in the government’s new warning.”

Mr. Ossowski also expects that the Trump administration’s claims will also open more class actions in state courts. He notes that Mr. Kennedy made his wealth as a plaintiff attorney suing companies.

“He’s very familiar with this modus operandi, and it’s been very clear from most of his actions at HHS, that that’s how he views the world, and in the world where all companies are bad,” Mr. Ossowski says.

Around 50 million Americans use products containing acetaminophen each week and more than 25 billion doses are used annually. Expect to see a lot more TV advertising from law firms seeking clients for class action suits, Mr. Ossowski predicts. He says the lawsuits “continue to muddy the waters around proper science and pharmaceuticals.”

Mr. Ossowski says drug companies will likely become more cautious about how much they advertise and the claims they make about the drugs. “Not necessarily because of anything wrong with their drugs, but solely because they don’t want to be penalized by the government,” Mr. Ossowski says.

“So effectively, you could see a long-term chilling of innovation for pharmaceuticals, drug makers, medical devices, basically any product that touches either the FDA or HHS, which in our country is plenty,” Mr. Ossowski adds.