New Study Shows Inconclusive Acetaminophen-ADHD Link During Pregnancy

New data examining prenatal acetaminophen exposure and its potential link with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASDs) in children produced mixed results, leaving pharmacists and clinicians without a clear answer on debated risks.

According to JAMA Pediatrics researchers, their findings highlight unaddressed sources of bias within the exploration of this link and the study designs used to examine it.¹

“Acetaminophen is the most common over-the-counter (OTC) medication taken to relieve fever, pain, or discomfort during pregnancy,” wrote the authors of the study. “Growing concerns about acetaminophen’s neurodevelopmental effects stemmed from cohort studies reporting dose-response–like associations between prolonged use of acetaminophen during pregnancy and the offspring’s risks for ADHD, ASDs, or worsened behavioral and brain function measures.”

A new cohort study of over 2 million births in Taiwan has added a complex layer to the high-stakes debate regarding maternal acetaminophen use and child neurodevelopment. Researchers found that although initial population-wide data suggested a link between prenatal prescriptions and subsequent diagnoses of ASD and ADHD, these associations essentially vanished in sibling-matched analyses.¹

However, the study’s bidirectional analysis yielded divergent results, leading authors to report that their sibling-matched data remained inconclusive due to unaddressed sources of bias that continue to plague observational research in this field.

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Continued Circulation of Conflicting Studies

This Taiwanese research reflects the findings of a massive 2024 Swedish study in JAMA that analyzed health records for nearly 2.5 million children.²

Like the Taiwan study, the Swedish investigators initially identified a small increased risk of neurodevelopmental disorders in the general population. Yet, when they compared siblings—where a mother took acetaminophen during one pregnancy but not another—the risk completely disappeared, suggesting that earlier findings were likely attributable to familial confounding rather than the drug itself.^2,3

Brian Lee, PhD, an epidemiology professor at Drexel University and lead author of the Swedish study, identifies genetics as the “elephant in the room” that accounts for a large portion of autism. He notes that the statistical association often seen between the drug and neurodevelopment is similar to the correlation between ice cream sales and drowning—while they rise together, the true driver is hot weather.³

In this clinical context, the underlying reasons for taking the medication, such as maternal infection, fever, or chronic pain, are likely the actual risk factors for the child.^2,3

A Volatile Regulatory Landscape

Despite this evolving scientific evidence, the regulatory and political landscape has moved toward increased caution. In September 2025, the FDA initiated a safety label change for acetaminophen and notified physicians of a possible link to neurological conditions.⁴

Although acknowledging that a causal relationship has not been established, the agency emphasized the need for parents and physicians to be aware of the “considerable body of evidence” suggesting potential risks. This regulatory shift was part of a broader push by the Trump administration, which included a $50 million investment in the Autism Data Science Initiative and a nationwide educational campaign led by the Department of Health and Human Services (HHS).^4,5

President Trump and HHS Secretary Robert F. Kennedy Jr. recommended that pregnant individuals limit acetaminophen use, though they recognize that acetaminophen remains the only approved OTC option for treating high fevers, which pose significant fetal risks.

For pharmacists, these developments underscore a critical responsibility in patient counseling and interdisciplinary care. As front-line providers, pharmacists are uniquely positioned at the intersection of medication management and health information.⁵ They must help patients navigate a highly heterogeneous body of scientific evidence while acknowledging that alternatives like aspirin and ibuprofen have their own well-documented adverse impacts on the fetus.^4,5

Although legal torts have attempted to hold manufacturers liable for not warning of these risks, federal courts have recently excluded certain expert opinions, noting that major medical organizations still caution against drawing causal inferences.⁵

Experts suggest that even though the scientific needle is pointing toward no causal effect, pharmacists should continue to advise that medications only be taken when medically indicated and never in doses exceeding physician recommendations.^2,3 This transparent communication is essential as pharmacists help patients manage the uncertainty inherent in prenatal care.^3,5

“This cohort study conducted in Taiwan found associations between pregnancy exposures to acetaminophen and the offspring’s ADHD or ASDs in the full cohort but not in the sibling-matched analyses,” concluded the authors of the current study.¹ “The substantial divergence in associations in the sibling design when assessing whether the older or the younger sibling was prenatally exposed to acetaminophen suggests that additional biasing issues undermine the validity and prevent firm conclusions from being drawn using the sibling design.”

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REFERENCES

1. Lee P, Chuang Y, Hu Y, et al. Maternal acetaminophen use and child neurodevelopment. JAMA Pediatr. March 09, 2026. doi:10.1001/jamapediatrics.2026.0071

2. Ahlqvist VH, Sjöqvist H, Dalman C, et al. Acetaminophen use during pregnancy and children’s risk of autism, ADHD, and intellectual disability. JAMA. 2024;331(14):1205–1214. doi:10.1001/jama.2024.3172

3. Winny A. Understanding the evidence on pregnancy, Tylenol, and autism. Johns Hopkins Bloomberg School of Public Health. October 7, 2025. Accessed March 17, 2026. https://publichealth.jhu.edu/2025/the-evidence-on-tylenol-and-autism

4. FDA responds to evidence of possible association between autism and acetaminophen use during pregnancy. News Release. FDA. September 22, 2025. Accessed March 17, 2026. https://www.fda.gov/news-events/press-announcements/fda-responds-evidence-possible-association-between-autism-and-acetaminophen-use-during-pregnancy

5. Gallagher A. Trump Administration claims link between autism and acetaminophen use in pregnancy. Drug Topics. September 23, 2025. Accessed March 17, 2026. https://www.drugtopics.com/view/trump-administration-claims-link-between-autism-and-acetaminophen-use-in-pregnancy