The European Medicines Agency (EMA) said that there was no new evidence that would require changes to the region's current recommendations for the use of paracetamol, known as Tylenol in the United States, during pregnancy.
The US President Donald Trump urged pregnant women not to take Tylenol over an unproven link to autism, and urged major changes to the standard vaccines given to babies.
A World Health Organization spokesperson said that evidence of a link between the use of paracetamol during pregnancy and autism remained inconsistent and that the value of life-saving vaccines should not be questioned.
"The evidence remains inconsistent," WHO spokesperson Tarik Jašarević told a Geneva press briefing when asked about a possible link between paracetamol use in pregnancy and autism.
"We know that vaccines do not cause autism. Vaccines, as I said, save countless lives. So this is something that science has proven, and these things should not be really questioned," he added.
Medical professionals have long cited acetaminophen as among the safest painkillers to take during pregnancy, especially as fever and pain can also pose dangers to both the mother and the developing foetus.
"Available evidence has found no link between the use of paracetamol during pregnancy and autism," the EMA said in a statement, adding paracetamol could be used during pregnancy when needed though at the lowest effective dose and frequency.
The president-elect of the Psychological Society of Ireland has said that comments made by Mr Trump on the use of paracetamol by pregnant women is "more than worrisome".
Speaking on RTÉ's Morning Ireland, Dr Sarah Cassidy said that the comments made by Mr Trump were dangerous.
"I think research takes a long time to do," she said, "and as a person who has spent a lot of my career conducting research, I think that it's really, really worrisome that information about vaccines, which have been entirely discredited, would be brought back into the media.
"This doesn't belong in the media ... I think this is dangerous."
Dr Cassidy advised women to speak to their medical doctors if they or a small child or baby has a fever.
"Tylenol, acetaminophen have been shown to be safe in doses as approved by medical doctors and by the FDA and by a number of different scientific outlets.
"So, I have no concerns about that," she said.
In relation to autism, she said that it is not a disease "nor is it an epidemic", adding that to even discuss it "in those terms is what is worrisome".
Dr Cassidy said that the number of people being diagnosed with autism is due to better diagnosis and more awareness.
"It is true that the rate of diagnosis has increased, but I don’t think that the numbers of people who are autistic has increased," she said.
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"I think our methods of assessment and our tools and our sensitivity and specificity, I think that is what has improved. I think that's what's better now."
Meanwhile the company Kenvue, which makes Tylenol, has said that it strongly disagrees with any suggestion of acetaminophen causing autism.
In a statement it said: "The facts are that over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism.
"We stand with the many public health and medical professionals who have reviewed this science and agree."
Monique Botha, a professor in social and developmental psychology at Durham University, says there is no robust data that shows taking paracetamol during pregnancy increases the likelihood of a child being diagnosed with autism.
Autism, ADHD ad learning disabilities are primarily genetic, she said.
Speaking on RTÉ's Today with Claire Byrne, Professor Botha said the Trump administration is muddying the water on an emotive topic and it is an abuse of power.
"There were a lot of statements that were made yesterday that have no evidence base, including, for example, the ludicrous claim that the Amish community doesn't particularly experience autism.
"It's not true, the claim that the MMR vaccine is better taken spread out instead of as a combi vaccine. Again, there's no evidence for this," she said.
MMR vaccine
Kingston Mills, Professor of Experimental Immunology, Trinity College, said the MMR vaccine is incredibly effective and protects against potentially deadly diseases in young children.
Humans get infected with multiple pathogens all the time, Professor Mills said, and we respond to them and recover.
"The evidence is that we get infected with multiple pathogens all the time in our nose. We could have, in our nose, two or three different viruses at the same time that cause the common cold, and we respond to them, and we recover from cold.
"So we have the ability to respond to multiple pathogens, these are bacteria, viruses, all the time. It's the same with a vaccine. We've the ability".
Speaking on RTÉ's Today with Claire Byrne, he said he hoped that the Trump administration's take on the MMR would not affect uptake rates in Ireland where people are "well informed and pretty sensible".
