When President Donald Trump flatly proclaimed at a press conference on September 22, 2025 that pregnant women should not take Tylenol, I immediately thought of my own experiences during my second birth. While pushing for almost three hours, I developed an infection in the uterus called chorioamnionitis, which occurs when bacteria infect the uterus, placenta, and sometimes the baby’s bloodstream. I had a fever and my baby’s heart rate was significantly elevated.
I remember feeling delirious; My colleague and friend, while attending the birth, said that she had never seen me in that state. I couldn’t concentrate on pushing. I felt like I was fainting and worried about my baby.
And I remember the incredible relief that acetaminophen, the active ingredient in Tylenol, gave me by reducing my fever and slowing my heart rate and that of my baby. After taking it, I was able to push with confidence and welcome my healthy daughter, who is now 7 years old and growing wonderfully.
As a practicing obstetrician and medical researcher with nearly two decades of experience caring for pregnant patients, I have to make a dozen decisions about acetaminophen use every day when I work in the hospital. I have examined the data as a researcher, clinician, and educator. A fundamental aspect of our work is balancing the risks and benefits of any treatment.
The president’s words will not change my medical practice, but I am concerned that they will create confusion for my patients and fear of potential lawsuits for all practicing healthcare professionals.
The American College of Obstetricians and Gynecologists, the leading organization that guides medical decisions about pregnancy and childbirth, reiterated the safety and effectiveness of acetaminophen use during pregnancy, given the confusion surrounding Trump’s claims.
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Mixed messages
I first looked into the data on possible links between acetaminophen and developmental disorders a few years ago, when I received a call from a woman who recently found out she was pregnant and had contracted the flu from her young son. She was worried that Tylenol was dangerous for her developing baby. Some studies suggest links between acetaminophen use during pregnancy and neurodevelopmental disorders, such as attention-deficit/hyperactivity disorder (ADHD) and autism. However, they lack a crucial distinction.
First, they cannot determine precisely whether acetaminophen use during pregnancy itself was associated with the child’s neurodevelopmental disorders, or whether the fever and other symptoms that led people to use the pain reliever influenced the outcome. Second, because these studies rely on statistical associations rather than controlled experiments, they cannot demonstrate cause and effect.
Since it is unethical and unfeasible to conduct a controlled study that evaluates the real risks of acetaminophen use, the best alternative to control for environmental or genetic factors is to analyze maternal exposure to acetaminophen and the outcomes of more than one child in each family.
That’s exactly what was done in a 2024 Swedish study that looked at nearly 2.5 million children born between 1995 and 2019 in Sweden to mothers who had documented medication use during pregnancy. When looking at children individually, researchers found up to a 5% increase in autism in those exposed to acetaminophen during pregnancy. However, when siblings were included in the analysis, controlling for environmental, medical and genetic factors that might have contributed, the small elevated risk disappeared.
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Fever during pregnancy is dangerous for mother and baby
There are many important reasons why doctors like me may recommend acetaminophen to a pregnant patient. A pregnant patient I saw with the flu was so sick that she had a septic infection, meaning the infection had spread throughout her body. Her 40°C fever and dangerously low blood pressure threatened her life and that of her fetus.
My colleagues and I did not hesitate to treat her with acetaminophen. Our goal was to reduce not only their body temperature, but also the heart rate of the fetus, since a high heart rate can be dangerous stress for the fetus. I shudder to think what would have happened to her and her baby if she had been denied this medication or been afraid to use it after hearing a statement from Trump and his health officials.
Fever is very common during pregnancy; around 20% of patients report having experienced it.
In fact, the evidence for a connection between fever during pregnancy and autism is much stronger than any study linking acetaminophen to autism. Recurrent fever during pregnancy can increase the risk of autism by up to 300%, especially in pregnant patients with severe or long-term infections. This is especially true if the patient is hospitalized, as is the case with most of my patients, whose cases are severe enough to require hospitalization.
Pain during pregnancy
In addition to fever, which can occur during pregnancy and childbirth, as I personally experienced, pregnant patients may seek to manage pain, which can occur for a variety of reasons over the course of nine months.
Pregnant women suffer from kidney stones, appendicitis, or cavities that require a root canal, just like people who are not pregnant. Up to 70% of pregnant women experience back pain, which can prevent them from doing their normal daily activities and caring for their children. Should they be denied pain medication and told to suck it up?
The safest and most recommended pain reliever for them is acetaminophen.
Other pain relief options, such as nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, are generally prohibited during pregnancy as they can cause closure of a major heart valve in the fetus, as well as low amniotic fluid and other complications. Opioids carry the risk of the fetus developing addiction and withdrawal syndrome, not to mention the risk of addiction in the mother.
For me, the ability to guide people through pregnancy, childbirth, and beyond is the most intimate and rewarding part of medicine. The anxiety and fear that people bring to my office and the delivery room because of the many uncertainties associated with pregnancy and childbirth are palpable and legitimate.
That’s why it’s critical that all recommendations are sound and evidence-based, with a clear understanding of the nuances and limitations of research studies. I know that every time I look at my children, I think about everything I can do to keep them safe and wonder what I could have done in the past to prevent the problems we are currently facing. We owe it to parents like me and all future parents to provide them with the most honest and scientific information possible.
*Tami S. Rowen is Associate Professor of Obstetrics, Gynecology, and Gynecologic Surgery, University of California, San Francisco
This text was originally published in The Conversation
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