A wide-ranging review into paracetamol use by pregnant women has found no convincing link between the common painkiller and the chances of children being diagnosed with autism and ADHD.
Publication of the work was fast-tracked to provide prospective mothers and their doctors with reliable information after the Trump administration urged pregnant women to avoid paracetamol – also known as acetaminophen or Tylenol – claiming it was contributing to rising rates of autism.
Speaking at the White House in September, the US president said women should talk to their doctor about limiting the use of the painkiller while pregnant and followed up with far stronger language, telling women to “fight like hell” not to take it.
While rates of autism have risen in recent decades, many scientists believe the trend is driven by greater awareness, improvements in diagnosis and a substantial broadening of the criteria doctors use to describe the condition.
In an umbrella review published in the British Medical Journal on Monday, researchers analysed previously published scientific reviews on whether paracetamol raised the likelihood of pregnant women having children who are diagnosed with autism or ADHD.
They concluded the quality of the reviews ranged from “low to critically low”, while any apparent link between the painkiller and autism was probably explained by family genetics and other factors.
Prof Shakila Thangaratinam, a consultant obstetrician and senior author on the review at the University of Liverpool, said: “Women should know that the existing evidence does not really support a link between paracetamol and autism and ADHD.
“If pregnant women need to take paracetamol for fever or pain then we would say please do, particularly because high fever in pregnancy could be dangerous to the unborn baby.” Alternative painkillers such as ibuprofen are not recommended during pregnancy.
The researchers examined nine systematic reviews. These included 40 observational studies into paracetamol use during pregnancy and autism, ADHD and other neurodevelopmental conditions in children. All of the reviews reported at least a possible association between a mother’s paracetamol use in pregnancy and autism or ADHD in their children, but seven urged caution when interpreting the findings because they did not rule out other factors.
Only one review included two studies that properly accounted for family genetics and other shared factors such as the mother’s pre-existing health conditions. One, published last year, found rates of autism, ADHD and intellectual disability were marginally higher in 2.4 million Swedish children whose mothers took paracetamol in pregnancy. But when the authors compared siblings who were exposed to the painkiller with those who were not, the effect disappeared. This suggests that rather than paracetamol, the mother’s genetics, underlying health conditions or other shared environmental factors were responsible.
“If there’s a family history of autism and ADHD, either in the parents or the siblings, then it is likely that that is the reason a child is diagnosed rather than something the mother took in pregnancy,” said Thangaratinam.
Beyond providing an overview of the evidence, the findings should reassure women who might feel guilty for taking paracetamol during pregnancy. “They might have a child that is autistic with ADHD and we really don’t want them to think it’s because of something they did in pregnancy. That’s a terrible feeling for a mother to have,” said Thangaratinam. “There isn’t anything in the current evidence that suggests mothers taking paracetamol is actually causing autism and ADHD.”
Prof Dimitrios Siassakos, an honorary consultant in obstetrics at University College London, said the review confirmed what experts around the world said after Donald Trump’s comments.
“Paracetamol is the safest medication to use in pregnancy, and has been used by the majority of pregnant women globally for several decades without any impact on autism and ADHD,” Siassakos said. “It is also the safest to use if there is maternal fever, whereas untreated high temperature is a risk factor for poor pregnancy outcomes, including adverse foetal outcomes. High temperature and inflammation have a negative impact on foetal and neonatal brains and untreated inflammation can cross the placenta.”
