Acetaminophen Use During Pregnancy and ADHD Risk in Offspring: Evaluating the Evidence

Recent media reports have highlighted a potential link between acetaminophen (Tylenol) use during pregnancy and increased risk of Attention Deficit Hyperactivity Disorder (ADHD) in offspring. This research summary examines the current evidence, including a recent small-scale study that garnered media attention and larger population studies that provide important context to these claims.

Background

Acetaminophen is the most commonly used pain medication during pregnancy, with approximately 40-65% of pregnant women taking it at some point during gestation according to the National Institutes of Health1. Given this widespread use, any potential association with neurodevelopmental outcomes merits careful scientific evaluation.

Previous Research

Multiple studies have previously investigated the potential association between prenatal acetaminophen exposure and ADHD risk, with mixed results. Some studies have found associations while others have not1. An important limitation of many earlier studies was the failure to control for a crucial confounding factor: genetic transmission of ADHD risk from mother to offspring1.

Confounding Factors

Women with ADHD are more likely to experience conditions that might lead to acetaminophen use during pregnancy, including:

• Higher rates of headaches and migraines
• More reports of fibromyalgia and pain conditions
• More general bodily complaints including joint and spinal pain1

This creates a potential confounding relationship where acetaminophen use might simply be a marker that the mother has ADHD symptoms herself rather than a causal factor for offspring ADHD1.

Recent Study Claiming Increased Risk

Methodology

A study published in Nature Mental Health in early 2025 examined the associations between maternal blood biomarkers of prenatal acetaminophen exposure, placental gene expression, and ADHD risk in offspring1.

• Sample size: 307 mother-child pairs
• Population: Exclusively African American participants
• Assessment: Blood samples during pregnancy and follow-up of children for ADHD diagnosis1

Results

The study reported:

• Approximately 2-3 times increased risk for ADHD in offspring of mothers who took acetaminophen
• The effect was primarily observed during second-trimester exposure
• The increased risk was almost entirely found in female offspring1

Limitations

The study had several significant limitations:

• Very small sample size compared to population studies
• Limited to one ethnic group
• Utilized only about 25-30% of the available participants from a larger study
• Did not control for family genetics and ADHD heritability
• No explanation for why effects were primarily seen in girls1

Larger Population Study

Methodology

A much more comprehensive study published in 2024 examined the entire Swedish population:

• Sample size: 185,900 mother-child pairs (approximately 600 times larger than the aforementioned study)
• Design: Included sibling control analyses to account for family genetics1

Results

The Swedish population study found:

• Only a very slight increase in ADHD risk associated with acetaminophen exposure
• When comparing exposed children to their unexposed full siblings (controlling for family genetics), the associations were dramatically weakened or became non-significant1
• No significant association between acetaminophen use during pregnancy and risk for autism, ADHD, or intellectual disability when appropriate sibling control analyses were conducted1

Expert Panel Review

An editorial published in Obstetrics and Gynecology in early 2025 provided a comprehensive review of the existing evidence:

• Examined 56 different studies, commentaries, and editorials
• Identified 9 high-quality studies for detailed analysis
• Reviewed existing meta-analyses1

Conclusions from Expert Panel

The expert panel concluded that:

• Most positive findings between acetaminophen exposure and ADHD risk are difficult to interpret due to important biases
• Studies had high degrees of selection bias, variability in selection criteria, and uncontrolled family confounding variables
• In studies controlling for genetics by comparing siblings, evidence of association was markedly reduced or became non-significant1
• According to current scientific evidence, prenatal exposure to acetaminophen is unlikely to confer a clinically important risk of childhood ADHD1

Conclusion

The current body of scientific evidence does not support a causal relationship between acetaminophen use during pregnancy and ADHD risk in offspring. When genetic factors are properly controlled for, any observed associations are greatly diminished or disappear entirely. The expert consensus is that the current level of evidence does not warrant changes to clinical guidelines on the treatment of fever or pain during pregnancy1.

Recommendations for Future Research

Future studies on this topic should:

• Use large, representative samples
• Implement proper controls for family genetics, particularly maternal ADHD status
• Employ sibling comparison designs where possible
• Consider potential sex differences in outcomes
• Use consistent methodologies and selection criteria to allow for better comparison across studies