What’s New Right Now?

In September 2025, U.S. officials announced plans to caution against widespread acetaminophen use in pregnancy, citing research suggesting possible links to autism and ADHD. While industry groups argue that the evidence isn’t definitive, this marks a shift in tone: it is now being acknowledged and brought to attention that prenatal acetaminophen exposure could carry developmental risks.

The Research Landscape

Some studies using cord blood acetaminophen metabolites find a dose-response association with later diagnoses of ADHD and autism—however, some large family-based analyses report no causal link.

So where’s the balance?

Associations exist in some datasets.
Strong causal proof is still lacking.
The biological mechanism of glutathione depletion remains a legitimate reason to be cautious.

What is Glutathione?

Glutathione is the body’s most powerful antioxidant, often called the “master detoxifier.” It helps protect cells from oxidative stress, supports liver detoxification, and recycles other antioxidants like vitamins C and E. Low levels of glutathione have been linked to inflammation, weakened immunity, and increased risk of chronic conditions.

Read more from my previous blog on Glutathione: The Master Antioxidant and it’s importance in Autism from last year.

Why Glutathione Matters

Acetaminophen is mostly metabolized safely, but a fraction becomes NAPQI, a toxic byproduct. Normally, the body’s glutathione (GSH) neutralizes NAPQI. But if GSH stores are low (from high-dose use, chronic illness, oxidative stress, or poor nutrition), NAPQI can accumulate and damage tissues.

In the liver, this causes the well-known risk of acetaminophen-induced liver failure.
In pregnancy and fetal development, reduced glutathione may leave the brain and placenta vulnerable to oxidative stress and inflammation.

This is why researchers have speculated for decades that frequent acetaminophen use in pregnancy could tip the balance in some mothers/children with already reduced glutathione reserves.

Bottom line: Even without definitive proof of an autism link, the glutathione-depleting effect gives a biologically plausible reason to use acetaminophen sparingly and strategically.

Acetaminophen and the Liver: A Known Risk for All

Leading cause of acute liver failure in the U.S. and U.K. when overdosed.
Risk worsens when multiple products containing acetaminophen are taken unknowingly.
Antidote: N-acetylcysteine (NAC), which replenishes glutathione.

Autism: A Multifactorial Condition

Even if acetaminophen contributes in some pregnancies, autism is not caused by one factor alone.

Genetics: Hundreds of small-effect variants create susceptibility.
Environmental exposures: Maternal infections, toxins, metabolic health, and possibly medications interact with genetic risk.
Timing and dose: The developmental stage matters—same exposure may have different outcomes depending on when it occurs.

This means autism risk is best understood as a complex interplay of genes and environments—not a single exposure or choice.

Guidance for Families

Cautious use: If acetaminophen is needed (e.g., for fever, which itself carries risks), use the lowest effective dose for the shortest time.
Avoid stacking products: Many cold/flu and pain relievers contain hidden acetaminophen.
Support glutathione naturally: Nutrient-rich diet, cruciferous vegetables, adequate sleep, and antioxidants can help maintain resilience.
Multifactorial focus: Broader prenatal health (nutrition, infection prevention, reducing toxins, stress management) supports neurodevelopment more than any single variable.

Bottom Line

Autism is multifactorial
But acetaminophen depletes glutathione, a master antioxidant crucial for detoxification and brain protection.
Given decades of mechanistic concern, plus mixed but concerning epidemiologic signals, prudent caution is justified.

REFERENCES:

References (APA)

Allison Parshall. (2025, Sept.). Does Tylenol use during pregnancy cause autism? What the research shows. Scientific American. Scientific American

Chun, L. J., Tong, M. J., Busuttil, R. W., & Hiatt, J. R. (2009). Acetaminophen hepatotoxicity and acute liver failure. Clinical Liver Disease, 13(2), 341–360. PubMed

Hinson, J. A., Roberts, D. W., & James, L. P. (2010). Mechanisms of acetaminophen-induced liver necrosis. Handbook of Experimental Pharmacology, 196, 369–405. PubMed Central

Ji, Y., Azuine, R., Zhang, Y., et al. (2019). Association of cord plasma biomarkers of in utero acetaminophen exposure with risk of attention-deficit/hyperactivity disorder and autism spectrum disorder in childhood. JAMA Psychiatry, 77(2), 180–189. PubMed Central

Merck Manual Professional. (2025). Acetaminophen poisoning. Merck Manuals

Nature News Staff. (2025, Sept.). Trump links autism and Tylenol: Is there any truth to it? Nature. Nature

PBS NewsHour. (2025, Sept.). Research doesn’t show using Tylenol during pregnancy causes autism—Here are 5 things to know. PBS

The Guardian Science Desk. (2025, Sept.). Is it safe to use paracetamol (Tylenol) during pregnancy? The Guardian

Yan, M., Huo, Y., Yin, S., & Hu, H. (2018). Mechanisms of acetaminophen-induced liver injury and its implications for therapeutic interventions. Acta Pharmaceutica Sinica B, 8(2), 147–158. PubMed Central

Ayoub, G., et al. (2025). Autism spectrum disorder as a multifactorial disorder. Journal of Personalized Medicine. PubMed Central

Love, C., et al. (2024). Prenatal environmental risk factors for autism spectrum disorder: A review. BMC Medicine, 22, 316. BioMed Central

Rubin, J. B., et al. (2018). Acetaminophen-induced acute liver failure is more common than other causes in the developed world. Clinical Gastroenterology and Hepatology. CGH Journal

StatPearls. (2023). Acetaminophen Toxicity. National Center for Biotechnology Information. NCBI

Johns Hopkins University Newsroom. (2019). Taking Tylenol during pregnancy associated with elevated risk for ADHD, autism. The Hub

Tylenol & Autism? What to Know