The President of the United States Donald Trump affirmed, Monday, September 22, that the use, during pregnancy, of paracetamol (an analgesic also called “acetaminophen” and marketed under the name Tylenol in the United States) would explain the increase in the number of autism diagnoses. He suggested that pregnant women should “endure without treatment” fever or pain rather than using this medication with analgesic (against pain) and antipyretic (against fever) effects.
“Tylenol during pregnancy can be associated with a very increased risk of autism.” – @POTUS pic.twitter.com/0FdBCOjtZk
— The White House (@WhiteHouse) September 22, 2025
This statement has caused concern and confusion around the world, but there is currently no solid scientific evidence to support Donald Trump’s claim. This is particularly what our own work revealed. Published in 2024, they covered nearly 2.5 million births in Sweden. However, they have not been able to demonstrate that the use of paracetamol during pregnancy increases the risk of autism in the child. This is the largest study carried out to date on the subject.
More than twenty-five years of data
To determine whether this molecule really represents a risk during pregnancy, we used data contained in the Swedish national health registers, which are among the most comprehensive in the world. Our study followed nearly 2.5 million children born between 1995 and 2019, for some of them up to the age of 26.
By combining prescription delivery data and interviews conducted by midwives during prenatal visits, we were able to identify mothers who reported having used paracetamol (around 7.5% of pregnant women) and those who claimed not to have used it during their pregnancy.
We also made sure to take into account variables likely to influence the results of our statistical analysis. We particularly considered factors such as fever or pain, which could have prompted a mother to use paracetamol when she was pregnant. The aim was to ensure that the comparison between the two groups was truly fair. We then became interested in children’s neurodevelopmental problems, in particular diagnoses of autism, attention deficit disorder with or without hyperactivity (ADHD) or intellectual disability.
The strength of our study comes from the possibility, thanks to these data, of comparing siblings. We were thus able to compare the trajectories of children born to the same mother, in cases where paracetamol had been used during one of the pregnancies, but not during the other. We studied more than 45,000 pairs of brothers and sisters, at least one of whom had been diagnosed with autism.
This system based on an intra-family comparison is powerful, because brothers and sisters share a large part of their genetic heritage and their family environment. In the case of neurodevelopmental disorders, it helps to distinguish whether it is the medication itself that is responsible for the problems, or whether it is more likely that the abnormalities are due to underlying family characteristics or conditions from which the mother may suffer.
Use of paracetamol and autism
Firstly, by looking at the scale of the entire population, we made the same observation as that made by previous studies. Children whose mothers reported using paracetamol during pregnancy were slightly more likely to be diagnosed with autism, ADHD or intellectual disability.
However, once comparisons between siblings were made, this association completely disappeared. In other words, when we compared siblings where one of the children had been exposed in utero to paracetamol and the other had not, the difference in probability of subsequently obtaining a diagnosis of autism, ADHD or intellectual disability disappeared.
Allowing a disease to develop without treating it during pregnancy can be dangerous. “Gritting your teeth,” as Donald Trump suggested, is therefore not a risk-free option.
Our study is not the only one to have sought to answer this question. Researchers in Japan recently published the conclusions of work based on a similar intra-family comparison system. Their results agree closely with ours.
Importantly, the Japanese scientists reproduced these conclusions in a population with different genetic background and where the use of paracetamol during pregnancy diverges significantly. In fact, in Japan, nearly 40% of mothers reported using this medication during their pregnancy. For comparison, less than 10% of Swedish mothers had used it. Despite these differences, the conclusion is the same. When comparing siblings, there is no evidence that paracetamol use during pregnancy increases the risk of autism or ADHD.
These results mark an important development compared to previous work, which was based on more limited data, smaller cohorts and which did not take genetic differences into account. They also did not document the reasons why some mothers used painkillers during their pregnancy, while others abstained from them.
However, this point may be important. Indeed, mothers who take paracetamol are more likely to suffer from migraines, chronic pain, fever or severe infections. However, we know that these conditions are themselves genetically linked to autism or ADHD, as well as to the probability, for their children, of being subsequently diagnosed with one of these conditions. In statistical science, this type of “confounding factor” (or “confusion factor”) can generate seemingly convincing associations, without necessarily reflecting a true cause-and-effect relationship.
“Grit your teeth”?
The question that many ask remains: how to interpret this information, if you are pregnant and suffering from pain or fever?
It is important to know that allowing a disease to develop without treating it during pregnancy can be dangerous. In a pregnant woman, the occurrence of a high fever can, for example, increase the risk of complications for both the mother and the baby. “Grit your teeth”as Donald Trump suggested, is therefore not a risk-free option.
This is why professional organizations such as the American College of Obstetricians and Gynecologists and the UK Medicines and Healthcare products Regulatory Agency continue to recommend paracetamol as the gold standard antipyretic and analgesic during pregnancy, at the lowest effective dose and only when needed.
In France, this is also the position of the National Agency for the Safety of Medicines and Health Products, which clarified, on September 25, that“There is currently no new data justifying a change in the recommendations for the use of paracetamol during pregnancy. Paracetamol (Doliprane, Dafalgan, Efferalgan, etc.) remains the safest medication to relieve mild to moderate pain and reduce fever during pregnancy.
There is no demonstrated link between the #paracetamol and autism
↪️ Currently, no new data justifies a modification of the recommendations for the use of paracetamol during #pregnancy
➕ information: https://t.co/ZACY3LSZXI pic.twitter.com/FsRpn3s1Kl— ANSM (@ansm) September 25, 2025
This is nothing more and nothing less than the recommendation that has been in force for decades. Of course, if, for one reason or another, a pregnant woman finds herself obliged to take paracetamol regularly, for a prolonged period, she must contact her doctor or midwife. But in any case, the idea that paracetamol use during pregnancy is a cause of autism is simply not supported by the strongest scientific data currently available.
The real danger is that such alarmist speech will dissuade pregnant women from treating their pain or fever and thus endanger their health and that of their child.
