United States President Donald Trump recently urged pregnant women to avoid paracetamol except in cases of very high fever, citing a potential link to autism. His comments have sparked renewed debate on the safety of one of the most widely used medicines in pregnancy.
Paracetamol also known as acetaminophen or Tylenol in the United States is often prescribed to relieve headaches, back pain, and fever during pregnancy. In Australia, the Therapeutic Goods Administration (TGA) has reiterated its position: paracetamol is safe for use at all stages of pregnancy. The drug is classified as Category A, meaning it has been widely used by pregnant women without evidence of increased birth defects or harmful effects on the fetus.
Doctors also caution that untreated high fevers during pregnancy can themselves be dangerous, raising the risk of miscarriage, congenital abnormalities such as cleft lip or heart defects, and even autism. That makes managing maternal illness with safe medications a priority.
How research has shifted
Concerns about paracetamol and child development are not new. In 2021, an international group of experts reviewed human and animal data and warned that paracetamol might disrupt fetal development. Since then, the evidence has been closely scrutinized.
Most recently, Harvard University researchers conducted a sweeping review of 46 studies on paracetamol use in pregnancy. Results were mixed: 27 studies reported links to neurodevelopmental disorders such as autism or ADHD, nine showed no significant associations, and four suggested possible protective effects.
The most influential study in this body of work examined nearly 2.5 million children born in Sweden between 1995 and 2019. While initial findings suggested a slightly higher risk of autism and ADHD in children exposed to paracetamol in utero, the signal disappeared when researchers compared full siblings one exposed to the drug, the other not. In these cases, there was no evidence of greater risk.
This type of “sibling analysis” is critical because it controls for shared genetics and home environment, both of which strongly influence neurodevelopmental outcomes. For example, siblings of autistic children already face a 20% chance of also being autistic, regardless of medication exposure.
Sorting cause from coincidence
A February review highlighted why the evidence remains confusing: many studies carry significant biases, from how participants were selected to how confounding factors were measured. When researchers accounted for these factors particularly within families the apparent link between paracetamol and autism largely disappeared.
That raises another possibility: what if it is not the paracetamol itself, but the underlying reason for taking it, such as fever or infection, that contributes to later health outcomes?
Beyond paracetamol
Autism is a complex condition with no single cause. Genetics play a central role, but researchers also study non-genetic influences, such as parental age, pregnancy complications, infections, smoking, alcohol use, socioeconomic factors, and even breastfeeding. Many of these variables are difficult to measure and rarely accounted for fully in research.
For now, most health authorities maintain the same advice: paracetamol remains the safest first-line option for pain and fever relief in pregnancy. The risks of untreated illness appear far greater than any unproven associations with autism.