Neither the painkiller Tylenol nor vaccines have been shown to cause autism, the World Health Organization have said, following comments from US President Donald Trump and his administration to the contrary.
Mr Trump insisted that pregnant women should "tough it out" and avoid Tylenol due to an unproven link to autism and also urged major changes to the standard vaccines administered to babies.
Medical groups have long cited acetaminophen, or paracetamol - the primary ingredient in Tylenol - as among the safest painkillers to take during pregnancy.
WHO spokesman Tarik Jasarevic acknowledged that some observational studies - which are based purely on observations and do not include control or treatment groups - had "suggested a possible association between prenatal exposure to acetaminophen or paracetamol and autism".
But, he told reporters in Geneva, "the evidence remains inconsistent" with other studies finding "no such relationship".
"If the link between acetaminophen and autism were strong, it would likely have been consistently observed across multiple studies," he said, warning against "drawing casual conclusions about the role of acetaminophen in autism".
'No evidence'
European medical regulators meanwhile said their recommendations that pregnant women can use paracetamol for pain relief had not changed.
"Patient safety is our top priority. There is no evidence that taking paracetamol during pregnancy causes autism in children," Alison Cave, safety chief at Britain's Medicines and Healthcare products Regulatory Agency (MHRA), said in a statement.
Steffen Thirstrup, chief medical officer at the European Medicines Agency, agreed.
"Our advice is based on a rigorous assessment of the available scientific data and we have found no evidence that taking paracetamol during pregnancy causes autism in children," he said.
Vaccines were also on the rambling agenda of Mr Trump's press conference yesterday, when he repeated anti-vax movement talking points.
He sowed doubt over standard vaccines including the MMR shot - which covers measles, mumps and rubella - and implied he would end the common use of aluminium in vaccines, the safety of which has been widely studied.
Identifying the root of autism - a complex condition connected to brain development that many experts believe occurs for predominantly genetic reasons - has been a pet cause of Mr Trump's health secretary, Robert F Kennedy Jr.
Mr Kennedy Jr has for decades spread claims that vaccines cause autism.
'As much evidence linking tea drinking to autism as paracetamol use'
The President of the Irish Medical Organisation, Dr Anne Dee, said there is as much high-quality evidence linking tea drinking to autism as there is to paracetamol usage.
Speaking on RTÉ's Drivetime, Dr Dee said the Trump administration linking the use of paracetamol during pregnancy to the development of autism in children is "unfair on women, wrong and false".
"The studies weren't well enough designed to be able to say that a tiny difference had any merit.
"The studies that were designed to be able to see, the groups were exactly the same, they showed no difference," she said.
Dr Dee added: "So we have no evidence that, in any study worth its merit, to show that there is a link between paracetamol and pregnancy, any more than we have between drinking tea and pregnancy.
"There is no evidence, it's one of the very few drugs that we've always considered safe for pregnancy and that women will reluctantly take if they have a headache, or a cold, or a flu when they're pregnant.
"But they need to be able to access these simple reliefs for when they are suffering in pregnancy.
"It is really, really unfortunate that that this would be said. There is absolutely no link at all."
