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This week's announcement by the White House linking the use of acetaminophen (Tylenol/Paracetamol) by pregnant women to a rise in autism is problematic because these OTC pain/fever relievers are considered the safest option for both the mother and unborn child.
We've previously looked at potential drivers of increased autism, and after genetics, environmental exposures, and increased recognition of those on the spectrum, fevers during pregnancy are frequently cited (see Molecular Psy.: Increased Autism Risk Linked To Prenatal Fever).
Taking away the only `presumed safe' option to reduce fevers could actually end up increasing the incidence of autism, instead of decreasing it. So too, could ACIP's recent move away from strongly recommending the COVID vaccine for pregnant women.
While a few studies have claimed a statistical link between acetaminophen use during pregnancy and autism (Link), none have found a causal link, and one of the most robust recent (2024) studies (see Acetaminophen Use During Pregnancy and Children’s Risk of Autism, ADHD, and Intellectual Disability) found:
Conclusions and Relevance Acetaminophen use during pregnancy was not associated with children’s risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.
Even the FDA - as of 2 days ago - finds no causal link has been established, writing:
It is important to note that while an association between acetaminophen and neurological conditions has been described in many studies, a causal relationship has not been established and there are contrary studies in the scientific literature.
It is also noted that acetaminophen is the only over-the-counter drug approved for use to treat fevers during pregnancy, and high fevers in pregnant women can pose a risk to their children. Additionally, aspirin and ibuprofen have well-documented adverse impacts on the fetus.
The American Academy of Pediatrics (AAP) released a statement on the White House Autism Announcement calling it `dangerous' and `misleading', as have others (see here & here).
Overnight the WHO weighed in, with the following statement:
WHO statement on autism-related issues
24 September 2025
The World Health Organization (WHO) emphasizes that there is currently no conclusive scientific evidence confirming a possible link between autism and use of acetaminophen (also known as paracetamol) during pregnancy.
Globally, nearly 62 million people (1 in 127) have autism spectrum disorder, a diverse group of conditions related to development of the brain. Although awareness and diagnosis have improved in recent years, the exact causes of autism have not been established, and it is understood there are multiple factors that can be involved.
Extensive research has been undertaken over the past decade, including large-scale studies, looking into links between acetaminophen use during pregnancy and autism. At this time, no consistent association has been established.
WHO recommends that all women continue to follow advice of their doctors or health workers, who can help assess individual circumstances and recommend necessary medicines. Any medicine should be used with caution during pregnancy, especially in the first three months, and in line with advice from health professionals.
Also, a robust, extensive evidence base exists showing childhood vaccines do not cause autism. Large, high-quality studies from many countries have all reached the same conclusion. Original studies suggesting a link were flawed and have been discredited. Since 1999, independent experts advising WHO have repeatedly confirmed that vaccines—including those with thiomersal or aluminum—do not cause autism or other developmental disorders.
Childhood vaccine schedules are developed through a careful, extensive and evidence-based process involving global experts and country input. The childhood immunization schedule, carefully guided by WHO, has been adopted by all countries, and has saved at least 154 million lives over the past 50 years. The schedule remains essential for the health and wellbeing of every child and every community. These schedules have continually evolved with science and now safeguard children, adolescents and adults against 30 infectious diseases.
Every vaccine recommendation by the Strategic Advisory Group of Experts on Immunization (SAGE), an independent advisory group to WHO, is grounded in rigorous review of evidence and carefully designed to offer the best protection against serious diseases and to be delivered when most needed.
When immunization schedules are delayed or disrupted, or altered without evidence review, there is a sharp increase in the risk of infection not only for the child, but also for the wider community. Infants too young to be vaccinated and people with weakened immune systems or underlying health conditions are at greatest risk.
Autism and neurodevelopmental disorders are among priority mental health and neurological conditions being discussed at the 4th UN High-Level Meeting on NCDs and mental health this Thursday, 25 September. As a global community, we need to do more to understand the causes of autism and how best to care for and support the needs of autistic people and their families.
WHO is committed to advancing this goal working together with partners including autistic-led organizations and other organizations representing persons with lived experience. WHO also stands with people who are living with autism and their families, a dignified community entitled to evidence-based considerations free of stigma.
With any medication there is always a risk-reward calculation involved: Is the risk (no matter how slight) worth the benefit from taking the medication.
There is, after all, no such thing as a 100% benign drug or vaccine (for 100% of the population). And anything - even life sustaining water and oxygen - can be toxic (or even fatal) if ingested in too high a dose.We've also looked at the dangers of of acetaminophen in high doses (see A Reminder To Know Your Dose). But, as the father of toxicology - Paracelsus (1493-1541) - famously stated : `The dose makes the poison".
For now, the mainstream medical community stands behind the rational use of acetaminophen during pregnancy, as the evidence of harm is insufficient.
While it is possible that additional evidence could change that stance, the risks of not treating a high fevers during pregnancy are well established, and is almost certainly the greater risk.
