What do we know about the causes of autism?
Autism is hereditary, and numerous studies have estimated that the causes of the disorder are 70 to 80 per cent genetic.
“We see a lot of people who want to know, ‘Why is my child autistic?’” said Kennedy, also a clinical geneticist. “We do lots of genetic tests, and we are finding increasingly genetic causes for autism.”
There is no single cause of autism; hundreds of genes are involved and, to a much smaller degree, an array of environmental factors is still under investigation.
When it comes to pregnancy, “there are some drugs that are linked to autism. Paracetamol is not one of them,” Kennedy said.
Valproic acid, an antiepileptic medication, has been associated with an increased risk of autism and autistic traits in offspring when taken during pregnancy, and the viral illness, rubella, during pregnancy is also linked to autism in offspring.
Autism rates have increased dramatically in the past 30 years, but many experts say this is due to an expanded definition of autism spectrum disorder and improved diagnostic screening, resulting in more diagnoses.
What is the most robust research investigating paracetamol and autism risk?
Experts say the most convincing study on paracetamol and autism was a Swedish analysis of data from almost 2.5 million children born between 1995 and 2019, published last year. The researchers looked at which children had been diagnosed with autism and reviewed medical records to see whether their mothers had taken the drug.
They compared siblings where one was exposed to paracetamol before birth and the other was not. This is a powerful analysis method because siblings are close genetically, have similar upbringings and share exposure to the same mother’s health, which helps researchers scrutinise the effect of more specific factors such as paracetamol.
This sibling analysis, the largest study to date on the risk of giving birth to a child with autism, found no link between the drug and autism.
‘It is sad that unqualified demagogues continue to disregard science.’
Dr Steven Kapp, member of the Coalition of Autism Scientists, UK
Another sibling study within an analysis involving 216,000 children in Japan released this month made similar conclusions, and the authors said their results suggested that the small increase in autism risk uncovered by other studies was down to confounding factors beyond paracetamol itself.
What is the evidence-based advice for pregnant women and pain relief medication?
Paracetamol is recommended for pregnant women who want relief from mild pain, headaches, toothaches, muscle pain and especially fever.
“People don’t take medication for the fun of it. They’re taking it to treat an underlying condition that can have real risks for their babies,” Kennedy said. “Pregnant women should not be scared to treat fever because that can be really harmful.”
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Maternal fever of more than 38 degrees for at least 24 hours has been associated with an increased risk of miscarriage and some malformations, including neural tube defects like spina bifida in early pregnancy and stillbirth in later pregnancy.
“The safest option for fever control in pregnancy is paracetamol,” NSW Health advises. “The recommended dose is 1g (= 2 x 500mg tablets) up to four times a day (total maximum daily dose of 4g/day).
“Taking paracetamol at the recommended doses has not been shown to increase the risk for pregnancy loss or birth defects.”
It’s a category A drug in Australia, which means it is taken by a large number of women, with no evidence of defects or harm, and the Therapeutic Goods Administration (TGA) has no current safety investigations for paracetamol and autism.
Sarah Tooke, a veteran Sydney midwife and owner of the Sarah Tooke Childbirth & Parenting Education, said paracetamol had been safely used in pregnancy for decades.
“While headlines can sometimes cause necessary worry, parents can feel reassured that current expert guidelines, including those from the TGA, still support its use in pregnancy when taken as directed,” Tooke said.
“Any questions about medicines in pregnancy are best discussed with your doctor or midwife, but there is no evidence that changes the long-standing advice around paracetamol,” she said.
Why can’t pregnant women take ibuprofen?
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Pharmaceutical pain relief options are otherwise very limited for pregnant women. Importantly, non-steroidal anti-inflammatory drugs like ibuprofen (for instance, Nurofen) should not be taken during pregnancy as they can harm the fetus, especially if taken after 30 weeks of gestation.
Research shows these medications can cause low amniotic fluid and affect blood flow to the baby, causing serious heart problems, congenital malformations, miscarriage and stillbirth.
But if women take it accidentally, experts say not to panic and to talk to their doctor.
Pregnant women should speak to their doctor before they start taking any new medication, or change or stop taking anything.
What do the makers of Tylenol say?
Tylenol manufacturer, Kenvue, said that having evaluated the available science, “we continue to believe that taking acetaminophen does not cause neurodevelopmental disorders, including autism, and global health regulators, independent public health organisations, and medical professionals agree”.
“Acetaminophen is one of the most studied medications in history, including more than a decade of analysis and regulatory review by the US,” a Kenvue spokesperson said in a statement.
“We are concerned about the potential for consumer confusion and misinformation about the safety of taking acetaminophen during pregnancy, particularly as cough, cold and flu season approaches.”
What do we need to know about Trump’s ‘treatment’ for autism?
The Trump administration’s touted approval of Leucovorin, a drug given to chemotherapy patients, as a “treatment” for autism has also been treated with scepticism by researchers, who say there are no large, independent studies yet to back its efficacy.
“There is a long history of a cottage industry of false causes and ‘treatments’ offered for autism that prey on desperate people’s hopes and fears,” Kapp, of the Coalition of Autism Scientists, said. “It is sad that unqualified demagogues continue to disregard science.”
Pregnant women and new mothers can contact MotherSafe – a free telephone counselling service for women and their healthcare providers concerned about drug or environmental exposures during pregnancy and breastfeeding.
https://www.seslhd.health.nsw.gov.au/royal-hospital-for-women/services-clinics/directory/mothersafe
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