Sept 5 (Reuters) - U.S. Health Secretary Robert F.

Kennedy Jr. plans to announce a link between autism and prenatal

exposure to the popular over-the-counter pain and fever medicine

Tylenol, sold generically as acetaminophen in the United States

and paracetamol in the UK, the Wall Street Journal reported on

Friday.

WHAT DOES THE RESEARCH SAY ON ACETAMINOPHEN USE DURING

PREGNANCY?

There is no firm evidence of a link between the use of

the drug and autism. Recent studies have yielded conflicting

conclusions on whether its use during pregnancy might

create risks for a developing fetus.

A 2024 study of nearly 2.5 million children in Sweden found

no causal link between in utero exposure to acetaminophen and

neurodevelopmental disorders like autism spectrum disorder or

attention deficit hyperactivity disorder.

A 2025 review of 46 earlier studies did suggest a link

between prenatal acetaminophen exposure and increased risks of

these conditions, but the researchers from the Icahn School of

Medicine at Mount Sinai, Harvard University and others said the

study does not prove the drug caused the outcomes. They advised

that pregnant women should continue to use acetaminophen as

needed, at the lowest possible dose and for the shortest

possible period.

Large 2025 studies from Europe and Japan have suggested that

what might appear to be small associations between prenatal

acetaminophen use and neurodevelopmental disorders might

actually be due to confounders, that is, other underlying

factors - such as environmental conditions, parents' health and

genetics, other medications the mothers may have been taking,

and illness.

WHAT ARE THE MEDICAL GUIDELINES FOR PREGNANT WOMEN?

Acetaminophen/paracetamol is the recommended first-line

medication for pain and fever during pregnancy in guidelines

from the American College of Obstetricians and Gynecologists,

Britain's Royal College of Obstetricians and Gynecologists, and

other medical organizations.

Use of ibuprofen, naproxen and other nonsteroidal

anti-inflammatory drugs in the third trimester can lead to birth

defects, both societies warn.

Pregnant women should talk to their doctor if they plan to

take any of these medications, ACOG advises.

WHAT ARE THE RISKS OF NOT REDUCING FEVER DURING PREGNANCY?

Untreated maternal fever and pain during fetal development

can increase the risks of birth defects such as heart

conditions, abdominal wall defects, and neural tube defects in

which the brain and spinal cord do not form properly. Untreated

pain and fever has also been linked with preterm birth, low

birth weight, and miscarriage.

In pregnant women, untreated fever and pain can cause high

blood pressure, dehydration, depression and anxiety, and other

health problems.

WHY IS THE SUBJECT IN FOCUS NOW?

Assertions of a potential link have been a focus of

lawsuits brought by parents and autism activists in the United

States against retailers, charging they failed to warn consumers

that Kenvue's ( KVUE ) Tylenol and its generic versions could

cause ADHD or autism.

In December 2023, a U.S. federal judge struck a blow to

hundreds of such lawsuits, barring expert witnesses from

testifying after finding they lacked scientific evidence for

their claims.

In August 2024, citing that ruling, the judge dismissed all

the cases in federal court. A U.S. appeals court is slated to

hear arguments next month in an appeal of that ruling, court

records show.