Does Tylenol Use in Pregnancy Cause Autism?

For years, researchers have tried to point to a cause for autism spectrum disorder, which is a condition related to brain development. Recently, there have been some broad claims that a cause for autism has been found: Tylenol use in pregnancy. And, just to help put your mind at ease, the research we have does not back that claim.

What is autism?

Autism is a neurodivergent condition. Those with the neurotype can have many different symptoms, but typically process information differently than their neurotypical counterparts—their brains work a little (and sometimes a lot) differently. (Though the term neurodivergent can also be used for people with ADHD and dyslexia, too.) 

Those with autism typically have characteristics that distinguish them from others socially, including trouble communicating or challenges with social interaction, though the diagnosis can also include symptoms like behaviour repetition, struggles with changes in routine, and sensory sensitivity. Characteristics of autism are commonly noticed in early childhood, and that’s when many receive a diagnosis.

How do you treat autism?

Treatment often revolves around personalized therapies to help improve communication or help with the activities related to everyday life. Other symptoms, like anxiety, can be managed with therapy or medication. The right environment and routines (and of course, support) can be a big help in managing symptoms.

What causes autism?

The short answer? We don’t fully know. What we do know is that there’s a strong link to genetics and parental age. What doesn’t cause autism? Vaccines (this myth is consistently debunked by studies and research). And we don’t have enough research to conclusively say that Tylenol use during pregnancy causes autism, either. Some studies show a potential association, but other studies (like the recent 2024 JAMA study—more on that below) show no such association.

Is Tylenol use in pregnancy safe?

There are many medications that you cannot take while pregnant, but Tylenol is not currently one of them. Tylenol (the brand most predominantly associated with over-the-counter acetaminophen or paracetamol) is a painkiller—one of the only ones that is safe for use during pregnancy, especially to manage fever or pain (which we know can harm fetal health). Alternatives, like not taking anything when you have a high fever or using other drugs like ibuprofen, have known and well-established risks, which means Tylenol remains one of the only options for pain and fever management during pregnancy that has few risks. The recommendation is to talk to your doctor and to use Tylenol at the recommended dose and for the shortest time possible, if you are pregnant. This is backed by the Society of Obstetrics and Gynaecologists of Canada (SOGC) and the American College of Obstetrics and Gynaecologists (ACOG). 

Tylenol vs acetaminophen vs paracetamol

Acetaminophen and paracetamol are the same medication—there is no difference in the structure or composition. They simply go by different names in different parts of the world. Tylenol is the brand most commonly associated with acetaminophen, and has become the common term for over-the-counter pain relief (fun fact, this is known as a genericized trademark or generic mark—other examples include Kleenex or Google). 

Why is Tylenol being connected with autism?

Like we mentioned, there are a few studies that show a potential association between acetaminophen use in pregnancy and autism. But, it's important to note that association, correlation, and causation are not the same thing. No studies currently show that Tylenol use in pregnancy causes autism. And there are a few well-done studies that show it doesn't.

In 2024, a Swedish study looked at the link between autism and Tylenol. It included more than 2 million children and looked specifically at siblings to take into account the strong genetic connection that we know exists in autism. 

What they found was that acetaminophen use during pregnancy was not associated with a child’s risk of autism, ADHD, or intellectual disability. When they studied siblings where one had been exposed to acetaminophen in utero and the other was not, there was no increased risk of autism in the exposed sibling. 

The takeaway? It’s good to remember that correlation (two things happening together) does not equal causation (one thing directly causing the other thing). For example, ice cream sales and shark attacks both rise in the summer, but they aren’t connected. This is why the sibling control in the Swedish study is so revealing.

Why are autism rates going up?

The numbers around childhood autism rates have gone up significantly in recent years (from 1:150 in 2000 to 1:31 today). But that’s because we have more research and understanding of what autism is, can better diagnose it, and the criteria to diagnose autism has been broadened over the years. People have always been autistic; we’re just better at identifying it now. We’re still working on understanding it and, perhaps most importantly, reducing the stigma associated with it.