Current evidence does not link paracetamol use during pregnancy to autism, experts said after a new review of studies on this hypothesis, according to The Lancet.
US President Donald Trump said in September that there had been a "meteoric rise" in autism cases and that Tylenol - which is called paracetamol in the UK - was a possible cause.
He said the painkiller should not be taken during pregnancy. Trump's statement was criticized by autism activists and scientists in the UK and around the world.
Experts said they hoped the latest study would "settle the issue".
Researchers conducted an extensive review on the issue, which was published in the journal The Lancet Obstetrics, Gynaecology and Women's Health.
An international team of academics, including experts from the UK, searched research databases for all studies reporting risk estimates for autism, attention deficit hyperactivity disorder (ADHD) and intellectual disabilities.
Eligible studies compared pregnancies with and without exposure to paracetamol, and examined validated questionnaires or medical records on medical outcomes.
They also looked at other illnesses the mothers had and other treatments they had received.
Some 43 studies were included in a systematic review – a comprehensive examination of data – and 17 studies in a meta-analysis – a research method for systematically combining findings from multiple studies.
A number of so-called “sibling comparison studies” were also included.
These studies compare children born to the same mother, in a pregnancy where she took paracetamol and in another pregnancy where she did not take paracetamol.
The authors concluded that exposure to paracetamol during pregnancy was not associated with the risk of autism spectrum disorder, ADHD, or intellectual disability.
