Understanding FDA's Tylenol and Pregnancy Warning, Endorsement of Access to Drug for Autism

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On September 22, 2025, the U.S. Food and Drug Administration (FDA) announced two important steps to protect children’s brain health.

The agency is beginning the process of adding new warnings to acetaminophen (Tylenol and similar products) about possible risks when used during pregnancy.

At the same time, the FDA has approved leucovorin calcium tablets for a rare condition called cerebral folate deficiency (CFD), which can cause developmental delays and autistic features.

Tylenol and Pregnancy: What Parents Should Know

Acetaminophen is the most common over-the-counter medicine used in pregnancy, often to reduce fever or ease pain. But new evidence has raised concerns about its safety for unborn babies.

• Link to autism and ADHD: Large studies, including the Nurses’ Health Study II and the Boston Birth Cohort, suggest children exposed to acetaminophen in the womb have about a 20–30% higher risk of autism or attention-deficit/hyperactivity disorder (ADHD).
• Risk strongest with long-term use: The greatest concern appears when acetaminophen is taken regularly throughout pregnancy.
• Developing livers may be vulnerable: A newborn’s liver is still immature, limiting its ability to process the drug.
• Debate continues: Not all studies agree. Researchers have not proven that acetaminophen directly causes autism or ADHD.

FDA Commissioner Marty Makary, M.D., cautioned doctors to “consider minimizing the use of acetaminophen during pregnancy for routine low-grade fevers,” while reminding patients that ibuprofen and aspirin remain unsafe options during pregnancy.

The Numbers to Know:

• 1 in 36 U.S. children is now diagnosed with autism.
• 1 in 9 children will experience ADHD.
• 65% of pregnant women report using acetaminophen at least once during pregnancy.

New Hope for Cerebral Folate Deficiency

In a separate action, the FDA approved leucovorin calcium (also known as Wellcovorin) for patients with cerebral folate deficiency. CFD is a rare disorder where the brain cannot properly absorb folate, a vitamin critical for healthy brain development.

CFD symptoms can include:

• Developmental delays with autistic features (trouble with social communication, sensory issues, repetitive behaviors)
• Seizures
• Problems with movement and coordination

The FDA reviewed published studies and case reports from 2009–2024 and concluded that leucovorin can help individuals with CFD.

"We have witnessed a tragic four-fold increase in autism over two decades. Children are suffering and deserve access to potential treatments that have shown promise," said Makary noted.

The FDA is working with GSK, the maker of Wellcovorin, to update the drug’s label so it can be used safely in both adults and children with CFD.

“This effort reflects the FDA’s commitment to identify opportunities to repurpose drugs to treat chronic diseases. The FDA remains committed to finding and treating the root causes of autism," explained George Tidmarsh, M.D., Ph.D. director of the FDA’s drug center, explained:

Why It Matters

These FDA actions highlight two sides of the same concern: preventing harm during pregnancy and expanding treatment options for children with neurological challenges.

• For pregnant women: Use acetaminophen only when needed, in the lowest dose for the shortest time, and always consult your doctor first.
• For families with CFD: A newly approved treatment may improve care and quality of life.
• For the autism community: The FDA is paying closer attention to both potential risks and potential therapies.

Bottom Line

The FDA is sending a clear message: children’s brain health is a top priority. By warning about possible risks of acetaminophen during pregnancy and approving leucovorin for cerebral folate deficiency, the agency is helping families and doctors make safer, more informed decisions.