Autism Ontario Responds to Recent Claims Linking Tylenol to Autism

Autism Ontario

Autism Ontario has observed with concern the recent public statements suggesting that the use of acetaminophen (commonly known as Tylenol) during pregnancy causes autism in children. We believe that these claims are misleading, and make it harder for people to make safe, evidence-based health decisions.  

We also recognize that claims suggesting autism could or should be prevented harm autistic people and reinforce dangerous narratives. Such framing undermines the humanity and dignity of autistic people, and Autism Ontario strongly rejects these implications.  

What we know

  • Autism is a lifelong, neurodevelopmental difference with a complex array of contributing genetic and environmental factors. (Bai et al., 2019; Carlsson et al., 2024; Wei et al., 2021; Public Health Agency of Canada, 2022; Canadian Academy of Health Sciences, 2022).
  • Scientific research does not support the claim that taking acetaminophen/Tylenol during pregnancy causes autism (Damkier, et al., 2024; SOGC, 2025; Health Canada, 2025).   

“Acetaminophen is the safest option we have for treating fever and pain during pregnancy. It is recommended by experts and is backed by science. Moreover, untreated fever or pain can be harmful and can lead to complications to both mothers and their baby.  To be clear, the evidence on autism being related to acetaminophen exposure during pregnancy is very weak. While early, smaller studies may have suggested there could be a connection, newer and large-scale studies have not found strong evidence to support this link.” - Dr. Evdokia Anagnostou, Vice President of Research and Director of the Bloorview Research Institute, Child Neurologist  

Concerns about the claims

  • Statements implying certainty where there is none can fuel misunderstanding, stigma, guilt, and anxiety among parents and autistic individuals.  

  • Oversimplified messages may discourage people from seeking medical advice, or from using medications when medically necessary, with unintended negative outcomes.

  • Public health guidance must be based on rigorous peer-reviewed evidence, transparent analysis, and good clinical practice.  

Autism Ontario remains committed to:  

  • Supporting high-quality research that respects autistic people and their families.

  • Public discussion about autism that is grounded in evidence, sensitivity, and respect for the autistic community and their families.

  • Providing clear, evidence-based information and advocating for further research grounded in respect, transparency, and rigorous science.

  • Promoting understanding, acceptance, and inclusion of autistic people.  

Autism Ontario values public conversations that respect autistic individuals and their families. Claims connecting acetaminophen to autism without conclusive evidence risk misunderstanding and stigma. We remain dedicated to promoting awareness, inclusion, and understanding through accurate information and respectful dialogue. Above all, we affirm the worth, dignity, and rights of autistic people.

For more information, please email Autism Ontario’s Media Team at media@autismontario.com.

 

References:

Bai, D., Windham, G. C., Sourander, A,. Francis, R., Yoffe, R., Glasson, E,. Mahjani, B., Suominen, A., Leonard, H., Gissler, M., Buxbaum, J., Wong, K., Schendel, D,. Kodesh, A., Breshnahan, M., Levine, S. Z., Parner, E. T., Hansen, S. N., Hultman, C., Reichenberg,  A., & Sandin, S.  (2019).  Association of genetic and environmental factors with autism in a 5-country cohort. JAMA, 76(10), 1035-1043.   

Carlsson, T., Molander, F., Taylor, M. J., Jonsson, U., & Bolte, S. (2021). Early environmental risk factors for neurodevelopmental disorders–A systematic review of twin and sibling studies. Development and psychopathology, 33, 1448-1495.   

Damkier, P., Björkström Gram, E., Ceulemans, M., Panchaud, A., Cleary, B., Chambers, C.,  Weber-Schoendorfer, C., Kennedy, D., Hodson, K., Grant, K., Diav-Citrin, O., Obican, S., Shechtman, S., & Alwan, S. (2024).  Acetaminophen in pregnancy and attention-deficit and hyperactivity disorder and autism spectrum disorder. Obstetrics and gynecology, 145.

Government of Canada. Canadian Academy of Health Sciences. (2022). Autism in Canada: Considerations for future public policy development - Weaving together evidence and lived e…. Ottawa (ON): The Oversight Panel on the Assessment on Autism, CAHS.)  

Health Canada. (2025). https://recalls-rappels.canada.ca/en/alert-recall/acetaminophen-recommended-treatment-fever-and-pain-during-pregnancy Health Canada (2025).   

Public Health Agency of Canada. (2022). Autism Spectrum Disorder: Highlights from the 2019 Canadian Health Survey on Children and Youth, [Catalogue number HP35-153/2022E-PDF], Government of Canada.   

 Wei, H., Zhu, Y., Wang, T., Zhang, X., Zhang, K., & Zhang, Z. (2021). Genetic risk factors for autism-spectrum disorders; A systematic review based on systematic reviews and meta-analysis. Journal of Neural Transmission, 128, 717-734.