Donald Trump is reportedly expected to claim there is a link between the use of paracetamol in pregnancy and the development of autism – but what does the evidence say?
Americans consume more than 40% of all the world’s paracetamol, spending in excess of $4bn a year on products containing acetaminophen (as it is known in America – or by its leading brand name, Tylenol).
Autism rates in the US are also on the rise – going up from about one in 150 children in the year 2000, to around one in 30 today.
There have also been a number of well-publicised studies suggesting a correlation between mothers who took paracetamol during pregnancy and the birth of a child with autism or other neurodevelopmental disorders such as ADHD.
So surely something must be going on?
Well, not necessarily.
In studies that have suggested a link, the authors have been unable to show the drug itself led to autism instead of other factors.
These include: the genetics of the parents (autism’s genetic links are well established); the lifestyle or environment in which the mother lives; or most confounding of all, that the reason the mother was taking paracetamol – a viral infection perhaps – wasn’t a trigger rather than the drug itself.
A study showing a correlation is not the same as finding a cause.
Better understanding of autism has meant the criteria for diagnosing it have expanded over the last two decades to include far more people. Diagnoses may well be rising simply because we’re better at recognising it.
Tylenol is America’s leading brand name for paracetamol. Pic: AP
What’s more, there are numerous studies showing evidence of no link to paracetamol at all.
Chief among them is a huge study from last year that included 2.5 million children in Sweden.
In Sweden, a mother’s use of paracetamol during pregnancy is added to her medical records.
The researchers found a marginal increase in the risk of autism and paracetamol use by the mother. But crucially, when they included data for siblings born to the same mothers from pregnancies during which she took no paracetamol, the apparent link disappeared.
“Which provides a pretty strong evidence against the notion that paracetamol would cause harm,” said Dr Viktor Ahlqvist at the Karolinska Institute in Stockholm, who led the study.
Paracetamol still recommended in UK
The study showed not only that paracetamol wasn’t linked to autism, but that other studies, with poorer quality data were prone to seeing a pattern that wasn’t there.
This balance of evidence is why health authorities, including here in the UK, are confident in recommending paracetamol for use in pregnancy.
In fact, it’s now recommended as the safest choice, as other painkillers – even ibuprofen – have been shown to cause potential or actual harm to mother or babies.
Talking up a link with the drug could anger people with autism or their parents, say experts. Pic: iStock
While most doctors would advise women only to take medicines in pregnancy when necessary, avoiding paracetamol could do more harm than good.
“While you’re pregnant, experiencing uncontrolled fevers or some of the side effects from pain, such as high blood pressure, will be a lot more detrimental to a developing baby and a mother than paracetamol will be,” said Dr Monique Botha, who studies bias in autism research at the University of Durham.
Talking up a link between autism and paracetamol is also likely to anger people with autism or their parents, suspects Dr Botha.
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“Families with autistic children are often struggling with under-resourced care and someone standing up and declaring that they’ve potentially found the cause of autism – when it’s so misguided – isn’t going to change anything for them.”
Researchers worry too, that posing a link between a drug taken during pregnancy and autism adds unnecessary stigma to mothers of autistic children.
“We’ve seen this many, many times, going back to the scary stories of the 1960s, that the blame is usually on the mother and parents where a child has a condition,” said Dr Ahlqvist.
“With this current [US] administration, they’re again pointing the finger at mothers, when we have no substantial evidence to suggest that this is the case.”
So, if paracetamol doesn’t cause autism, what’s causing the Trump administration to talk about it?
With echoes of previous, and all too real, drug scandals like thalidomide, it’s the kind of story to generate controversy by association – however false.
And the Trump White House has form when it comes to finding issues to distract from genuine controversies surrounding the president.
The story also fits a key theme of US health secretary Robert F Kennedy Jr’s policy moves – like on childhood vaccines — that stem from his belief that children are being harmed by an overmedicated America.
But the whole point of science is that it doesn’t care what you believe, it’s about what the best quality evidence tells you.
So far, there’s been precious little of that behind the latest changes in US health policy.
