What Is the Science Behind the Paracetamol Autism Scare?

The science behind the concern linking paracetamol (acetaminophen) use during pregnancy to autism risk involves epidemiological studies suggesting a possible association between prenatal exposure to paracetamol and an increased risk of neurodevelopmental disorders, including autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and intellectual disabilities in children. The proposed mechanisms include paracetamol-induced alterations in cytokine levels, oxidative stress, disruption of prostaglandin synthesis, and dysregulation of neurotransmission in the developing fetal brain, particularly affecting dopaminergic pathways. It is known that paracetamol reduces glutathione levels, which can lead to oxidative stress.

Controversy and Mixed Results in Research

However, this association remains controversial and not definitively proven. Large-scale cohort studies provide mixed results, with some showing a slight increase in risk, while others, including sibling-controlled analyses, suggest that familial factors or confounding variables might explain the observed associations rather than a direct causal effect of paracetamol itself. Biochemical studies have raised hypotheses about oxidative stress and immune system changes, but conclusive molecular evidence in humans is lacking.

Summary of Current Findings

In summary, while there is suggestive evidence that prenatal paracetamol exposure may modestly increase the risk of autism and other neurodevelopmental issues, current scientific findings emphasise the need for further research to clarify causality and underlying mechanisms before changing clinical recommendations for paracetamol use in pregnancy.

Dr Tim Trodd

Family Medicine, Functional Medicine, General Practice

MBBS (London)
DCH (London)
DRCOG (UK)
MRCGP (UK)
FHKAM (Family Medicine)

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References

Andrade, C. (2021). Acetaminophen Use During Pregnancy and Children's Risk of Autism, ADHD, and Intellectual Disability. JAMA. Available at: https://jamanetwork.com/journals/jama/fullarticle/2817406
Andrade, C. (2021). Use of acetaminophen (paracetamol) during pregnancy and the risk of autism spectrum disorder in the offspring. The Journal of Clinical Psychiatry. Available at: https://www.psychiatrist.com/jcp/acetaminophen-paracetamol-during-pregnancy-risk-autism
Liew, Z., Ritz, B., Virk, J., and Olsen, J. (2016). Maternal use of acetaminophen during pregnancy and risk of autism spectrum disorders in childhood: A Danish national birth cohort study. Autism Research. Available at: https://onlinelibrary.wiley.com/doi/10.1002/aur.1591
Cannell, J. J. (2014). Role of Paracetamol in the Pathogenesis of Autism Spectrum Disorder: A Growing Perspective. International Journal of Epidemiology. Available at: https://ejmanager.com/fulltextpdf.php?
Tovo-Rodrigues, L., Schneider, B. C., Martins-Silva, T., et al. (2019). Is intrauterine exposure to acetaminophen associated with emotional and hyperactivity problems during childhood? Findings from the 2004 Pelotas birth cohort. BMC Psychiatry. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6245767/
Golding, J., Gregory, S., Clark, R., et al. (2020). Associations between paracetamol (acetaminophen) intake between 18 and 32 weeks gestation and neurocognitive outcomes in the child: A longitudinal cohort study. Paediatric and Perinatal Epidemiology. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7217049/