Taking acetaminophen during pregnancy has been associated with an increased risk of autism, and ADHD in children in some research. A new study suggests that it is not acetaminophen that is linked to neurodevelopmental disorders, but likely other issues such as genetics.
The new report, published in JAMA on Tuesday, focused on data from more than 2 million Swedish children who were followed for up to 26 years. After an initial analysis that revealed a very small increased risk of neurodevelopmental disorders in children whose mothers took acetaminophen during pregnancy, the researchers went back to the same database and did a second study, looking at pairs of siblings whose mothers used acetaminophen during one pregnancy but not the other.
This time they found there was no increased risk of neurodevelopmental problems associated with acetaminophen, which suggested there was something else raising the risk of these disorders.
Both the initial and sibling studies were published in the same report.
In this study as well as in earlier ones, researchers have had little information on whether the parents’ themselves had autism, ADHD or an intellectual disability. When the parents of the children in the study were young, diagnoses of neurodevelopmental disorders weren’t as common.
“The bottom line from this study is that pregnant women do not need to worry about autism if they use acetaminophen during their pregnancy,” said the study’s co-senior author Brian Lee, an associate professor at Drexel University’s Dornsife School of Public Health and a fellow at the A.J. Drexel Autism Institute.
Still, Lee said, “women should always consult with their physician before initiating medication use.”
Of the 185,909 children whose mothers took acetaminophen during pregnancy, about 9% were diagnosed with autism, ADHD or an intellectual disability. Among the estimated 2.3 million children whose mothers did not use acetaminophen while pregnant, about 7.5% were diagnosed with one of the conditions.
After adjusting for factors such as mother’s age, smoking status and maternal diagnoses of autism, ADHD and intellectual disability, the researchers found that among those children whose mothers had used acetaminophen during pregnancy, there was a 5% increased risk of autism, a 7% increased risk of ADHD and a 5% increased risk of an intellectual disability.
An estimated 2.8% of children will be diagnosed with autism by age 8, according to 2023 data from the Centers for Disease Control and Prevention; 11.3% of children and adolescents will be diagnosed with ADHD and 2.35% of children aged 3 to 17 will be diagnosed with an intellectual disability.
Dr. Catherine Caponero, an OB-GYN at the Cleveland Clinic said she was reassured by the results..
“This is a very well-studied drug during pregnancy,” Caponero said. “Studies have shown over and over again it is one of the few options women can use for pain and fever.”
Not treating fevers in moms could also be a problem, said J. Blake Turner, an assistant professor of social science 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 quite dramatically higher if it’s untreated,” he said.
The new study’s use of a sibling analysis highlights the importance of genetics, said Manish Arora, a professor of environmental medicine at the Icahn School of Medicine at Mount Sinai. The sibling analysis provides an adjustment that “is missing in many studies,” he said. “I really appreciated that.”