President Donald Trump on Monday claimed that an over-the-counter painkiller is linked to autism, and said US physicians would be notified immediately of the risk for use in pregnancy. Medical groups pushed back against the guidance, saying the commonly used drug is safe.
Mr Trump said the ingredient paracetamol, or acetaminophen as it is known in the US, was to blame for the development of the condition. He said drug labels would be updated.
"Effective immediately, the FDA will be notifying physicians at the use of ... acetaminophen, OK, which is basically commonly known as Tylenol, during pregnancy can be associated with a very increased risk of autism," Mr Trump said. "So taking Tylenol is not good."
US Health Secretary Robert F Kennedy Jr, under the slogan Maha, or Make America Healthy Again, has promised to find the causes of autism.
Mr Kennedy has said the increase in autism diagnoses in children in the US is happening at an “alarming rate”. He has rejected the argument that this rise is mainly due to better diagnosis tools and increased awareness, instead suggesting vaccines cause the disorder – a theory that has been debunked.
Earlier on Monday, the White House said the announcement said was evidence of the Trump administration's dedication to to health and transparency.
"This will be a powerful display of how the entire Trump administration is committed to addressing root causes of chronic conditions and diseases, embracing full transparency in government and championing gold-standard science," White House press secretary Karoline Leavitt said.
Tylenol has been identified by experts as one of the only safe pain relievers and fever reducers for pregnant women.
"Studies that have been conducted in the past show no clear evidence that proves a direct relationship between the prudent use of acetaminophen during any trimester and foetal developmental issues," the American College of Obstetrics and Gynaecology has said.
The Yale School of Public Health highlighted that frequent or prolonged acetaminophen use during pregnancy has been found to be associated with higher rates of neurodevelopmental disorders in children, but experts say those observational studies do not definitively prove that frequent Tylenol use during pregnancy causes autism.
"Until more definitive research is published, the US Food and Drug Administration and the CDC [Centres for Disease Control] continue to recommend acetaminophen as the safest over-the-counter pain reliever for pregnant women," it said.
Mr Kennedy said Health and Human Services would launch a nationwide public service campaign to inform families on the updates.
He also acknowledged that acetaminophen is often the only drug for fevers and pain in pregnancy, as others have well-documented adverse health effects.
"HHS wants, therefore, to encourage clinicians to exercise their best judgment and use of acetaminophen for fevers and pain in pregnancy by prescribing the lowest effective dose for the shortest necessary duration and only when treatment is required," Mr Kennedy said.
He said that there is evidence that taking pain relievers prolongs viral infections.
Experts say autism, a developmental condition that manifests itself on a spectrum, is a complex condition involving genetics and some environmental factors.
It can have an effect on social and emotional skills, as well as learning and language abilities. In mild forms, autistic people have impaired abilities to pick up on social cues, take part in social activities or focus on tasks. Some people with autism are nonverbal and have intellectual disabilities.
According to the CDC, about 3.2 per cent of eight year olds – or about one in 31 children – have had a form of autism diagnosed. Research suggests that the condition is more common in boys than girls. The cause of the disorder is largely unknown, despite decades of scientific research.
