Acetaminophen During Pregnancy Does Not Increase Autism, Study Finds.

A large new study published in JAMA Internal Medicine finds no evidence that acetaminophen during pregnancy causes autism.

Many pregnant women rely on acetaminophen (paracetamol) to relieve pain or reduce fever. In recent years, concerns have circulated about whether taking this common medication during pregnancy could increase a child’s risk of autism or attention-deficit/hyperactivity disorder (ADHD).

The Backstory

Last September, an announcement from the US Food and Drug Administration (FDA) sparked debate about the association between acetaminophen use during pregnancy and the risk of neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism. The FDA initiated a drug labeling change to reflect this potential hazard despite noting that studies had not established a casual relationship. The existing research at the time included a 2024 study of a large cohort in Sweden, which found a small increase in autism among children exposed to acetaminophen in utero. However, the association disappeared during a sibling control analysis, in which 1 sibling was exposed to acetaminophen in the womb and 1 was not. This type of comparison, the researchers explained, was meant to control for confounding factors such as genetics.

“When you compare moms who use acetaminophen vs moms who don’t, it’s apples to oranges,” said Brian Lee, PhD, senior author of the study and a professor of epidemiology at Drexel University Dornsife School of Public Health. He said that people who use acetaminophen are typically less healthy—hence the use of medication—and that they may have other common qualities that are hard to account for in a traditional analysis.

Why Were People Concerned?

In 2025, the U.S. Food and Drug Administration (FDA) announced plans to update acetaminophen labeling to mention a possible association with neurodevelopmental disorders. However, the FDA also emphasized that existing research had not proven a cause-and-effect relationship.

Some earlier studies suggested a small increase in autism risk among children exposed to acetaminophen during pregnancy. But researchers suspected that other factors—such as genetics, maternal health, or the reason for taking the medication—might explain the findings rather than the medication itself.

What Did the New Study Find?

Researchers analyzed health records from more than 708,000 mother-child pairs in Hong Kong between 2001 and 2023.

One of the study’s biggest strengths was its sibling comparison. Researchers compared siblings from the same mother where one pregnancy involved acetaminophen use and another did not. This approach helps reduce the influence of shared genetic and family-related factors.

The Results

The study found:

✅ No increased risk of autism or ADHD among children whose mothers used acetaminophen during pregnancy.

✅ No difference in risk based on:

• Which trimester the medication was taken
• The dose used
• How often it was taken

Interestingly, when researchers looked at the entire population without sibling comparisons, they observed a small association. However, they also found the same pattern when mothers used acetaminophen before pregnancy and after childbirth—times when the medicine could not affect fetal brain development.

This strongly suggests that the observed link is likely due to shared family or genetic factors, not the medication itself.

Why This Matters

Following widespread media coverage, many pregnant women became worried about taking acetaminophen. Surveys found that many people were unsure whether the medication truly increased the risk of autism, leading some to avoid it altogether.

This hesitation is concerning because:

• Acetaminophen is the only over-the-counter medication generally recommended to reduce fever during pregnancy.
• Untreated fever during pregnancy can pose risks to both the mother and the developing baby.
• Other common pain relievers, such as ibuprofen and aspirin, are generally not recommended during certain stages of pregnancy because they may harm the fetus.

Expert Opinion

The researchers say these findings add to growing evidence from studies in Hong Kong, Sweden, Taiwan, and Denmark, all reaching similar conclusions.

Experts believe the available evidence now strongly supports that acetaminophen does not appear to directly cause autism or ADHD when used during pregnancy as recommended.

Key Takeaway

Current evidence suggests that using acetaminophen during pregnancy, when medically needed and as directed, is not linked to an increased risk of autism or ADHD in children.

If you’re pregnant and need relief from pain or fever, it’s always best to talk with your healthcare provider before taking any medication, but this study provides additional reassurance that acetaminophen remains one of the safest options available during pregnancy.