'No evidence': medical experts reject autism claims

Australia's top medical authorities have emphatically rejected Donald Trump's claim of a link between paracetamol use in pregnancy and autism.

Chief medical officer Michael Kidd and the Therapeutic Goods Administration joined other global medicines regulators, leading clinicians and scientists worldwide in declaring "robust scientific evidence" showed no causal link between the use of paracetamol in pregnancy and autism or ADHD.

"Paracetamol remains the recommended treatment option for pain or fever in pregnant women when used as directed," the TGA said in a statement on Tuesday.

"Importantly, untreated fever and pain can pose risks to the unborn baby, highlighting the importance of managing these symptoms with recommended treatment."

Flanked by Health Secretary Robert F Kennedy Jr, the US president linked autism to the use of over-the-counter pain medication Tylenol.

Tylenol is an American brand of paracetamol and has the same main ingredient, acetaminophen.

No evidence was provided to back up the claim but the US Food and Drug Administration has moved to change acetaminophen product labels while issuing a letter to doctors saying the decision to take it "still belongs with parents".

Australian medical experts branded the claims as unhelpful and alarmist.

Many patients would now raise the issue with their GP, Royal Australian College of General Practitioners vice president Ramya Raman predicted.

"This announcement risks causing unnecessary alarm for pregnant women and must be approached with caution," Dr Raman said.

"The consensus of expert Australian researchers is that no published scientific studies have proved a causal relationship between paracetamol use during pregnancy and autism, only that there might be a link."

Margie Danchin, a clinician scientist at the University of Melbourne and Murdoch Children's Research Institute, said the claim was based on research that wasn't robust.

"It's not a clinical trial, it wasn't a randomised study, it wasn't even prospective," the Royal Children's Hospital consultant pediatrician told AAP on Tuesday.

"It's very concerning ... it's going to have serious health consequences."

Autism Awareness Australia chief executive Nicole Rogerson described the US announcement as "jazz hands and nonsense".

"There will be people here who listen to that who fall hook, line and sinker," Ms Rogerson said.

The president's suggestion that leucovorin, a form of folic acid, as a treatment for autism symptoms gave off "Ivermectin vibes", she said, referring to Mr Trump's endorsement of the unproven drug to treat COVID-19.

"He is feeding the world of the conspiracy theorists."

National Association of Specialist Obstetricians and Gynaecologists president Gino Pecoraro said Mr Trump's announcement was not helpful and had the potential to cause unnecessary anxiety for pregnant women and their families.

"Numerous studies have found association between paracetamol use and autism spectrum disorder but none have found causation," he said.

"Even in the studies suggesting association, the effect is very mild with only a 0.1 per cent increased rate (from 1.33 per cent to 1.42 per cent) in the largest Swedish study looking at 2.5 million children born between 1995 and 2019."

The TGA said paracetamol remained Pregnancy Category A in Australia, meaning it is considered safe for use in pregnancy.

"The TGA has no current active safety investigations for paracetamol and autism, or paracetamol and neurodevelopmental disorders more broadly."

Acting Prime Minister Richard Marles said he wouldn't give medical advice.

"Any advice or determinations which are coming out of the US FDA, we will obviously look at very carefully, but ? any woman out there who has any query about what drugs they should be taking during their pregnancy is a matter that they should take up with their doctor," he said.

The Kids Research Institute Australia autism researcher Andrew Whitehouse said evidence that leucovorin could treat autism was "weak".

"A few small trials suggest possible small improvements in behavioural outcomes, yet these studies are limited by small numbers, inconsistent findings, and a lack of independent replication," Prof Whitehouse said.

"Families and clinicians should be cautious, and also know that there are already many support programs with strong scientific backing that reliably support development in autistic children."

"Compared to these proven approaches, leucovorin is still very much unproven."