Donald Trump said he had been waiting 20 years to make an announcement linking paracetamol use in pregnancy to an increased risk of autism.
Speaking from the White House on Monday, surrounded by medical professionals and US health secretary Robert Kennedy Jr, the US leader also made a number of other health recommendations involving vaccines and a so-called autism “treatment”.
Various medical bodies, health professionals and charities have since rebuked many of his comments.
Here is what has been said.
Mr Trump began with warning pregnant women not to take paracetamol, or acetaminophen as it is known in America – or by its leading brand name, Tylenol.
Not backing up the claim with any scientific evidence, the White House later released a list of studies that it said have “evidence” of the link.
While an August study from Harvard University did suggest that taking Tylenol during pregnancy may lead to children developing neurodevelopmental disorders, including autism and ADHD, it recommended that pregnant women should take low-doses of acetaminophen or for a short period of time under medical guidance, rather than an overall “broad limitation” of the drug.
What do experts say?
Autism expert, David Mandell of the University of Pennsylvania, noted that while some studies suggest a link, many others haven’t found that concern.
For example, a far larger and more comprehensive Swedish study from last year, found no association between paracetamol, autism or other neurodevelopmental disorders.
Read more: What is autism?
Reacting to the president’s claim, Kenvue, the maker of Tylenol, stressed it does not believe taking acetaminophen causes autism.
“We strongly disagree with any suggestion otherwise and are deeply concerned with the health risk this poses for expecting mothers and parents,” it said in a statement.
Dr Alison Cave, chief safety officer of the UK’s Medicines and Healthcare products Regulatory Agency (MHRA), also said in a statement that there was “no evidence that taking paracetamol during pregnancy causes autism in children”.
She said paracetamol remains the “recommended pain relief option for pregnant women” in the UK and is important to manage untreated pain or fever that could pose risks to an unborn baby.
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The UK’s Health Secretary Wes Streeting urged pregnant women not to pay attention “whatsoever” to Mr Trump, adding: “I trust doctors over President Trump, frankly, on this.”
While Dr Zubir Ahmed MP, the UK’s patient safety minister, said on social media: “For the avoidance of any doubt, Paracetamol remains the safest painkiller to take during pregnancy.”
Further afield, the European Medicines Agency, said there was no new evidence that would mean its recommendations for the use of paracetamol during pregnancy would change.
Tarik Jasarevic, a World Health Organisation spokesperson, added that the links between the use of the drug and autism “remains inconsistent”.
On vaccinations, Mr Trump suggested that the MMR vaccine – a combined vaccine that protects against measles, mumps and rubella – should be taken in separate doses.
Mr Trump again did not cite any scientific evidence for the claim, instead saying: “This is based on what I feel.”
What do experts say?
NHS advice states that children should have three doses of the MMR vaccine, the first when they reach the age of one.
Until now, no country has recommended immunisation with three separate vaccines, according to the MHRA.
The regulatory body said single vaccines are also less safe than MMR because they leave children “vulnerable to dangerous diseases for longer”.
Elsewhere in the speech, Mr Trump said he recommends raising the age of when children are given the hepatitis B vaccine to 12 years old.
Hepatitis B is a liver infection that is spread through blood, semen and vaginal fluids.
What do experts say?
The NHS currently uses the 6-in-1 vaccine to protect against the infection, recommending babies as young as eight weeks old get their first dose.
The Centers for Disease Control and Prevention (CDC), America’s national public health agency, also recommends the vaccine for all infants, children and adolescents younger than 19 who have not been vaccinated, adults aged 19-59 and adults over 60 who have risk factors for the infection.
Before routine vaccination of American babies against hepatitis B, around 18,000 a year were infected with the virus in the first 10 years of life, either during birth, or as a result of living with someone with it. Nearly a quarter of those were likely to develop a chronic infection, leading to liver disease or liver cancer.
Since the vaccine was introduced, hepatitis B infections in US children have fallen by 95%.
Speaking after Mr Trump, Marty Makary, the commissioner of the Food and Drug Administration (FDA), announced that the government body is approving the use of leucovorin as a treatment option for patients with cerebral folate deficiency (CFD).
The FDA described CFD as a neurological condition that affects the transportation of folate – a vitamin essential for brain health – into the brain.
Low levels of folate can lead to a range of neurological symptoms, some of which are seen in people with autism.
Leucovorin, also known as folinic acid, works by boosting folate levels. It is currently used in the US to counteract the side effects of various prescription drugs, including chemotherapy and other high-dose medications that can negatively impact the immune system.
Read more:
Why are child vaccination rates so low?
What vaccines are children recommended to have and when?
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The FDA said it had analysed literature published on the topic between 2009-2024 and “has determined that the information supports a finding that leucovorin calcium can help individuals suffering from CFD”.
What do experts say?
While a handful of studies in recent years have suggested positive results when high-dose folic acid is used to treat children with autism, expert David Mandell, told AP that the studies are “really tiny” and larger, more rigorous trials would be needed to prove a concrete effect.
The Autism Science Foundation, a US charity, added that the science regarding leucovorin and autism “is still in very early stages, and more studies are necessary before a definitive conclusion can be reached”.
