For years, researchers have studied many factors (including genetics and environmental concerns) that may point to a cause for autism spectrum disorder, a condition related to brain development. Recently, there have been some broad claims suggesting 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 the assertion that acetaminophen causes autism. Major medical groups are still aligned that Tylenol is safe in pregnancy when used as directed for pain or fever. No new evidence proves causation, and the announcement has been criticized for sparking undue fear. What is autism? Autism is a neurodivergent condition, influenced primarily by genetics. Those with the neurotype can have many different symptoms and experiences, 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 challenges with communication and 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? Support often revolves around personalized therapies (like speech or occupational therapy) 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 these challenges. What causes autism? The short answer? We don’t fully know all the contributing factors of autism. 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 from organizations like the CDC and WHO). 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 high-quality studies (like the recent 2024 JAMA study—more on that below) show no such association. Association is not the same as causation, and currently, there is no clear evidence that supports Tylenol use in pregnancy causes autism. Is Tylenol use in pregnancy safe? There are many medications that you should not 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, if left untreated, 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 with fewer risks. Even with the recent news, the current recommendation remains the same: talk to your doctor if you’re experiencing symptoms like pain or fever during pregnancy, and use Tylenol at the recommended dose and for the shortest time possible. 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 for tissues or Google for searching online). Why is Tylenol being connected with autism? As mentioned earlier, several studies show a potential association between acetaminophen use in pregnancy and autism. But, it's important to note that association and causation are not the same thing. No studies currently show that Tylenol use in pregnancy causes autism. And there are other well-done studies that show it doesn't. For example, in 2024, a Swedish study looked at the link between autism and Tylenol use during pregnancy. The study checked records of more than 2.4 million kids born between 1995 and 2019. They compared brothers and sisters in the same families (since siblings share similar genes and home lives) to better control for things like family genetics, where one had been exposed to acetaminophen in utero and the other was not. They found that acetaminophen use during pregnancy was not associated with a child’s risk of autism, ADHD, or intellectual disability. The takeaway? It’s good to remember that association (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 one thing doesn't lead to the other—they're driven by something else (here it's hot weather, which makes people buy more ice cream and makes them more likely to go swimming). This is why the sibling control in the Swedish study is so revealing, as it was able to control for important variables like genetics and home environment. 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 experts and major organizations like the CDC attribute this primarily to improved awareness, broader diagnostic criteria, better screening practices, and increased access to evaluations, rather than a true rise in incidence. For example, rates for severe autism (with intellectual disability) have stayed stable over the past decade. We’re still working on understanding autism, its contributing factors, and, perhaps most importantly, reducing the stigma by embracing neurodiversity and providing supportive environments.
