The Lancet Study Reveals Sharp Decline in Tylenol Prescriptions

A groundbreaking analysis published in The Lancet on March 5, 2026, documents a significant drop in acetaminophen (the active ingredient in Tylenol) prescriptions for pregnant women visiting U.S. emergency rooms following high-profile warnings about potential autism risks. Researchers from Brown University School of Public Health and Harvard Medical School examined nearly 90,000 emergency department visits by pregnant individuals aged 15-44, revealing a 10% overall reduction in orders, equivalent to 22.5 fewer prescriptions per 1,000 visits. This decline peaked at 20% in the third week post-warning, highlighting the immediate influence of public statements on clinical practices.

The study, led by Michael L. Barnett from Brown University's Department of Health Services, Policy, and Practice, underscores the power of authority figures in shaping healthcare behaviors. While the drop was temporary—returning toward baseline by December 2025—it raises concerns about untreated pain and fever during pregnancy, conditions linked to adverse fetal outcomes.

Background: The September 2025 White House Briefing

On September 22, 2025, President Donald Trump, alongside Health and Human Services Secretary Robert F. Kennedy Jr. and FDA Commissioner Marty Makary, held a briefing claiming prenatal acetaminophen exposure contributes to autism spectrum disorder (ASD). Trump urged pregnant women to avoid Tylenol, stating it 'is not good,' while promoting leucovorin (folinic acid) as a potential autism treatment. This bypassed standard FDA processes, sparking widespread media coverage and public alarm.

Prior to this, observational studies like those from Harvard T.H. Chan School of Public Health and Mount Sinai suggested associations between acetaminophen use and neurodevelopmental risks, prompting FDA label review discussions. However, causal evidence remained weak, confounded by factors like genetics and maternal illness.

Study Methodology: Robust Data from Epic EHR Systems

Utilizing the Cosmos dataset from Epic electronic health records—covering over 1,600 U.S. hospitals and representing diverse demographics—the researchers conducted an interrupted time series analysis. They compared pre-briefing (June 30 to September 21, 2025) and post-briefing (September 22 to December 7, 2025) periods.

Key outcomes included observed-to-expected ratios (OER) for acetaminophen orders in pregnant vs. non-pregnant women aged 15-44, adjusted for trends and demographics. Comparators like opioids and Lactated Ringer's ensured specificity. For children aged 5-17, new outpatient leucovorin prescriptions were tracked against antipsychotics and folic acid.

• Sample: 88,857 pregnant ER visits; 853,216 non-pregnant female ER visits; 8.6 million pediatric outpatient encounters.
• Analysis: Poisson regression with weekly data.
• Strengths: Large, nationally representative U.S. sample; real-time prescribing capture.

Key Results: 10% Drop Specific to Pregnant Patients

Post-briefing, acetaminophen orders for pregnant ER patients fell to an OER of 0.90 (95% CI 0.86-0.94; p<0.001), with a 16% initial drop (OER 0.84) and 20% peak. No changes occurred in non-pregnant controls or comparators, isolating the effect.

Conversely, pediatric leucovorin prescriptions surged 71% (OER 1.71, 1.48-2.04), or 17.5 more per 100,000 visits, peaking at 113% week 2—despite lacking evidence for autism beyond rare cerebral folate deficiency.

Rise in Leucovorin: Promotion of Unproven Therapy

Leucovorin prescriptions for children jumped dramatically, reflecting the briefing's endorsement as an 'exciting therapy' for autism. While safe for certain deficiencies, off-label use risks side effects without proven benefits for ASD. Late increases in antipsychotics like aripiprazole suggest treatment-seeking spillover.

This dual shift—avoiding evidence-based pain relief while embracing unproven options—illustrates messaging pitfalls, per Brown researchers.

Academic Experts Weigh In on Study Implications

Lead co-author Jeremy Faust, from Harvard-affiliated Mass General Brigham, noted the 'overnight' impact: 'This is thousands of women not getting pain control or fever reduction when they need it.' Brown’s Michael Barnett emphasized authority figures' sway on practices.

Johns Hopkins' Caleb Alexander added: 'Words matter... they can change prescriber and patient behavior.' For career insights in public health research, explore academic CV tips at AcademicJobs.com.

Scientific Consensus: No Causal Link to Autism

A January 2026 Lancet Obstetrics, Gynaecology & Women’s Health meta-analysis of 43 studies (300,000+ pregnancies) found no association: ASD OR 0.98 (sibling studies), ADHD OR 0.95, intellectual disability OR 0.93. ACOG and AAP affirm acetaminophen's safety when used as directed.

Earlier associations likely reflect confounding (e.g., maternal fever/illness causing both acetaminophen use and risks). Untreated fever poses greater threats: neural tube defects, miscarriage.

Risks of Fever and Pain in Pregnancy: Why Tylenol Matters

Fever >100.4°F in first trimester triples neural tube defect risk; uncontrolled pain stresses maternal health. Alternatives like NSAIDs risk fetal heart/kidney issues. Guidelines recommend acetaminophen first-line.

• Step 1: Non-drug (rest, hydration).
• Step 2: Acetaminophen 500-1000mg q6h PRN, max 4g/day.
• Monitor: Consult OB if persistent.

University-led studies like this inform safer care.

Broader Public Health and Policy Implications

The study spotlights misinformation risks: rapid prescribing shifts without evidence, potential harm. Parallels COVID-era patterns. Calls for transparent FDA processes, clinician reliance on peer-reviewed data.

Brown University’s role exemplifies research jobs advancing policy.

University Research at the Forefront of Evidence-Based Insights

U.S. universities like Brown and Harvard drive discoveries via EHR analytics, interrupted time series—tools pivotal in postdoc opportunities. This work aids clinicians, policymakers in countering hype with data.

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Future Outlook: Balancing Caution with Care

Ongoing trials clarify long-term effects; monitor OTC use. Educate via trusted sources. Pregnant women: Discuss symptoms with providers. Researchers urge evidence vigilance amid influence.

For higher ed career advice in public health, visit AcademicJobs.com.

Photo by Erik Mclean on Unsplash

Conclusion: Informed Choices from Academic Research

The Lancet study illuminates messaging impacts, reinforcing acetaminophen's role when needed. Explore Rate My Professor, higher ed jobs, university jobs, career advice, or post a job to join impactful research.