Parents often ask whether common medical decisions, vaccinating a child, or taking acetaminophen during pregnancy, can cause autism. Both questions have been studied extensively. Here's what the research actually shows.
Do vaccines cause autism?
No,
vaccines
do not cause autism. The idea traces back to a 1998 paper that was later retracted after its data was found to have been falsified, and its lead author lost his medical license. In the decades since, dozens of large studies covering millions of children have looked for a link between childhood vaccines (including the MMR vaccine) and autism. None has found one.
Major reviews from the
CDC, the World Health Organization, the Institute of Medicine, and a
2025 evidence review from Johns Hopkins Bloomberg School of Public Health all reach the same conclusion: childhood vaccinations do not cause autism.
What vaccines
do is protect children from serious illnesses: measles, mumps, whooping cough, and others. That were once a routine source of childhood death and disability. Skipping or delaying vaccination raises real, preventable risk for both the child and the community.
Does acetaminophen during pregnancy cause autism?
The strongest evidence does not support a causal link.
Early
observational studies in the 2010s reported associations between prenatal acetaminophen use and higher rates of autism and ADHD diagnoses. Those studies had real limits: most relied on self-reported use, couldn't pin down dose or timing, and crucially couldn't separate the effect of the medication from the reasons women were taking it (fever, infection, pain, inflammation), which themselves can affect fetal development.
More recent, better-designed studies have changed the picture:
- A 2024 sibling-controlled study in
JAMA of nearly 2.5 million Swedish children found no increased risk of autism, ADHD, or intellectual disability in siblings exposed to acetaminophen in utero compared to siblings who weren't, a design that controls for shared family genetics and environment.
- A 2025
BMJ umbrella review of 46 systematic reviews concluded that apparent associations largely disappeared once genetic and environmental confounders were properly accounted for.
- A 2025 meta-analysis in The Lancet Obstetrics, Gynecology & Women's Health of roughly 60 studies found no causal link between acetaminophen used as directed during pregnancy and autism or ADHD in children.
- The New York State and New York City Departments of Health, in a joint October 2025 review, concluded that "no causal link has been established between prenatal acetaminophen exposure and autism spectrum disorder."
The American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Pediatrics (AAP) continue to recommend acetaminophen as the first-line option for pain and fever during pregnancy when used as directed. Untreated high fever during pregnancy carries its own risks to fetal development, which is part of why this guidance hasn't changed.
As with any medication, pregnant patients should make decisions in consultation with their own clinician.
