Pictured: Dr. Janine Hutson
September 29, 2025
Dr. Janine Hutson is a maternal-fetal medicine specialist and obstetrician/gynecologist (OBGYN) at London Health Sciences Centre (LHSC). Through London Health Sciences Research Institute (LHSCRI), she leads Canada’s only maternal drug safety research program using a placenta perfusion model to study how medications affect pregnancy. Her mission is to close critical knowledge gaps and ensure pregnant individuals have access to safe, evidence-based treatments.
We sat down with Dr. Hutson to talk about what patients need to know about Tylenol in pregnancy.
What is Tylenol and how does it work?
Tylenol is the brand name for acetaminophen, a common over-the-counter medicine used to relieve pain and reduce fever.
Acetaminophen works in the brain to help lower a fever by activating areas that control body temperature. For pain relief, it raises the body’s pain threshold, which means you feel less discomfort. It also blocks certain natural substances that cause or increase pain, helping you feel more comfortable while your body heals.
There is growing concern about a possible link between Tylenol and autism. But what does the science actually say?
This is a common question, and it’s important to separate speculation from established science.
Some studies have found no association between frequent or prolonged use of acetaminophen during pregnancy and autism, while others have. But an association simply means two things occur together – it does not mean one causes the other. These studies do not prove causation and often don’t account for other factors like maternal illness or fever, which can also affect fetal development.
Leading scientific and medical organizations, including the Society of Obstetricians and Gynecologists of Canada, agree any evidence to date is weak and fundamentally flawed.
So, Tylenol is still considered safe to use during pregnancy?
Yes. After reviewing all studies together, we are confident acetaminophen remains the safest and most effective option for pregnant patients when used at the lowest effective dose for the shortest time necessary.
Unlike NSAIDs such as ibuprofen or aspirin, acetaminophen does not interfere with fetal development or increase the risk of complications. That’s why it’s widely recommended by maternal-fetal medicine specialists, including our team here at LHSC.
Are there any risks associated with it?
While nearly all medications carry some degree of risk, acetaminophen has been used for decades and is considered safe when taken as directed.
In fact, avoiding acetaminophen when it's medically necessary may pose greater risks to the developing baby. Untreated fever has been linked to serious complications, including miscarriage, birth defects, fetal cardiovascular issues and a potential increased risk of autism. Similarly, unmanaged pain can contribute to maternal depression, anxiety and high blood pressure – all of which can negatively affect pregnancy outcomes.
The bottom line is the benefit of taking acetaminophen typically outweighs any potential risks.
What is LHSC doing to better understand medication safety and pregnancy?
Through LHSCRI, our team is using a placenta perfusion model to study how medications like acetaminophen cross the placenta and interact with fetal tissues. This research addresses a major gap in clinical knowledge, as pregnant individuals are often excluded from drug trials.
By generating direct evidence on how medications affect both mother and baby, our work helps inform safer, more confident decision-making during pregnancy.
What’s your message to expectant parents who are worried about the safety of Tylenol or other medications?
It's completely natural to have concerns during pregnancy, including when it comes to medication. The most important step is to speak with your health-care provider.
At LHSC, we strive to be a trusted source for maternal drug safety, helping pregnant individuals make informed decisions based on evidence, not fear or misinformation. We believe pregnancy should not mean suffering through pain or fever – and that medications like acetaminophen can be part of a safe and healthy pregnancy, when used appropriately.