Some research has associated paracetamol (also known as acetaminophen) use during pregnancy with an increased risk of autism and Attention Deficit Hyperactivity Disorder (ADHD) in newborns. A new study suggests, however, that it is not this drug that is related to neurodevelopmental disorders, but probably other issues such as genetics.
The new report, published Tuesday in JAMA, analyzes data from more than two million Swedish children who were followed up to age 26. After an initial study revealed a small increased risk of neurodevelopmental disorders in children whose mothers took acetaminophen during pregnancy, researchers reviewed the same database and did another study looking at sibling pairs whose mothers took acetaminophen. in one pregnancy but not during the other.
On that occasion, an increased risk associated with the drug was not observed, which suggested that there was another reason for the increased probability of these disorders. Both the initial study and that of the brothers were published in the same report.
In this analysis, as in previous ones, the researchers had little information about whether the parents themselves suffered from autism, ADHD or some intellectual disability, because, when they were young, the diagnoses were not as frequent.
“The bottom line of this study is that pregnant women don't have to worry about autism if they use acetaminophen during pregnancy,” said study co-senior author Brian Lee, a professor at Drexel University's Dornsife School of Public Health and member of the AJ Drexel Autism Institute.
Still, she added, “women should always consult with their doctor before starting the use of medications.”
Of the 185,909 children whose mothers took acetaminophen during pregnancy, about 9% were diagnosed with autism, ADHD or intellectual disability. Among the 2.3 million children whose mothers did not take paracetamol during pregnancy, around 7.5% were diagnosed with one of these diseases.
After adjusting for factors such as maternal age, smoking, and maternal diagnoses of autism, ADHD, and intellectual disability, the researchers found that among children whose mothers had used acetaminophen during pregnancy, there was a 5% increased risk of autism, 7% increased risk of ADHD and 5% increased risk of intellectual disability.
It is estimated that 2.8% of children will be diagnosed with autism by age 8, according to 2023 data from the Centers for Disease Control and Prevention (CDC); 11.3% of children and adolescents will be diagnosed with ADHD, and 2.35% of children ages 3 to 17 will be diagnosed with intellectual disability.
Catherine Caponero, a gynecologist and obstetrician at the Cleveland Clinic, was reassured by the results: “It is a very well-studied drug during pregnancy,” she commented, “studies have shown time and time again that it is one of the few options that women can use for pain and fever.
Not treating fever in mothers could also be a problem, said J. Blake Turner, professor of social sciences in psychiatry at Columbia University. Turner pointed to studies that have linked fevers during pregnancy to an increased risk of autism. “The risk can be much greater if it is not treated,” he stressed.
According to Manish Arora, a professor of environmental medicine at the Icahn School of Medicine at Mount Sinai, the use of sibling analysis in the new study highlights the importance of genetics. Sibling analysis provides an adjustment that is “missing in many studies,” he explained, “I really value that.”
