This past week, U.S. President Donald Trump drew sharp criticism from the scientific community after he urged pregnant women to avoid taking the popular pain reliever, paracetamol. Trump’s statements, made at an event on autism spectrum disorder at the White House, were condemned by scientists as an exaggeration of a minor correlation.
Helen Tager-Flusberg, the Director of the Center for Autism Research Excellence (CARE) at Boston University and co-founder of the Autism Scientists’ Coalition, called the administration’s statement “appalling.” According to her, it was “a very significant distortion of the scientific facts” about what science says regarding a possible link between paracetamol and autism.
“This message likely affected millions of pregnant women. Mothers of children with autism spectrum disorder will become so scared that they will think they caused their child’s autism, which is absolutely not true,” Tager-Flusberg said.
Research on the Link Between Paracetamol Use and Autism
A study published by Harvard University in August showed that women who took paracetamol during pregnancy were more likely to have children with an autism diagnosis. However, the study’s authors themselves noted that the findings did not constitute solid evidence and pointed only to a possible link between paracetamol and autism.
The study, published in the journal Environmental Health, determined that using paracetamol (acetaminophen) during pregnancy may be linked to an increased risk of neurodevelopmental disorders (NDDs) in children. The scientists reached this conclusion after analyzing 46 studies.
Of the 46 studies examined, the majority (27) indicated that taking paracetamol during pregnancy increases the risk of neurodevelopmental disorders in children, including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).
Furthermore, several studies showed that the longer or more frequently a pregnant woman took paracetamol, the more the risk increased. Although some studies found no link (9 studies) or even showed a contrary effect (4 studies), the overall picture still points to the existence of a risk.
However, Ann Bauer, an epidemiologist who worked on the study, told the media that she is concerned because it is premature for the federal government to issue recommendations, and the research community needs more evidence before political steps are taken.
David Mandell, a psychiatric epidemiologist at the University of Pennsylvania, notes that the potential risks associated with taking paracetamol to treat fever and pain during pregnancy are far less than the risks of an untreated infection. A high fever can harm both the mother and the fetus, while paracetamol reduces this risk.
For example, a recent study that observed the course of infections in pregnant women showed that fever is associated with multiple complications for both the mother and the fetus. The study, conducted from April to September 2023, included 80 pregnant patients who had a fever due to an infection.
Of the 80 cases studied, the most common causes of fever during pregnancy were urinary tract infections (31.3%) and upper respiratory tract infections (25%). Fever was associated with the following antenatal complications: abortion (13.8%) and premature delivery (23.7%). Fetal complications were also identified: prematurity (23.7%), low birth weight (40%), and infant mortality (2.5%).
Trump’s Statement on the Amish
Donald Trump named the Amish as an American community group that has “virtually no autism.”
Who are the Amish? The Amish are a Christian religious group primarily living in North America who live a secluded life away from the modern world. They reject technological advances such as electricity and cars and are often skeptical of modern medicine and vaccines.
Without any evidence, Trump stated that the low rate of autism among the Amish is likely due to their rare use of paracetamol.
However, as Professor Eva Loth of King’s College London states, the absence of autism among the Amish is “very, very unlikely.” According to her, the low statistical data is likely due to a lack of research in this community, and the Amish rarely seek a diagnosis from a doctor.
Although research on this topic is limited, a 2010 study that included 1,899 children in two large Amish communities in Ohio and Indiana showed that autism was present in approximately 1 out of every 271 children. This study, contrary to the information provided, confirms that autism spectrum disorder also exists in this community.
Trump also made a similar statement about Cuba, where he claimed there is a low rate of autism, which he linked to a shortage of paracetamol on the island. According to the World Health Organization, statistics on autism prevalence are unknown in most low- and middle-income countries.
Experts unanimously state that there is no scientific link between paracetamol and autism, and such unscientific claims cause confusion and fear in the public.
Why Have Autism Rates Increased in the United States?
According to experts, the increase in the number of autism diagnoses is mainly due to three factors. First, diagnostic rules have changed: the criteria have been broadened, making it possible to identify people with a wider range of symptoms on the spectrum. Second, public awareness of autism has increased, which has contributed to earlier diagnosis. Third, testing methods have improved.
Trump also stated that California has a “more serious problem” with autism. While data from the Centers for Disease Control and Prevention (CDC) shows that the state has the highest rate of autism among eight-year-old boys, the reason for this, according to the CDC, is a local initiative. As part of this initiative, hundreds of pediatricians have been trained to identify signs of autism in children at the earliest possible age and, if necessary, refer them for diagnosis, which has ultimately led to more widespread and accurate identification of autism cases.
Medscriptum Interview with Zaza Doborjginidze, a PhD Student in Philosophy of Science at the Hong Kong University of Science and Technology
Why is there such a big focus on autism in America now? Do you think the increase in prevalence in recent years reflects better diagnosis and broader criteria, or a real increase in incidence?
There are two main reasons for the increase in autism cases. The first is the expanded definition of autism, which means that more people now meet the diagnostic criteria than before. Second, today there are more public health programs, increased screening during preventive visits for 18-24-month-old children to check for signs of autism, and at the same time, parents’ awareness of autism symptoms is much higher than in the past.
However, it is not impossible that some of the increase in autism cases is not related to either the expansion of diagnostic criteria or improved screening. Among these factors are parental age—in developed countries, people are having children later and later—and the fact that the risk of autism is higher with premature birth, and with the development of neonatal care, infant mortality caused by premature birth decreases. There are also studies that point to the role of air pollution in the pathogenesis of autism. There is no single definitive answer as to what caused the increase in autism. It is likely a complex interaction of social, environmental, and biological factors.
What are “confounding” factors, and what environmental conditions could create the false impression that children of mothers who used paracetamol during pregnancy are more likely to have developmental problems?
“Confounding variables” in statistical studies mean when an external, third factor—which is related to both the independent variable (cause) and the dependent variable (result)—creates a false impression of a link between two phenomena. It distorts their true relationship and potentially leads to incorrect conclusions. In the case of paracetamol and pregnancy, those who take paracetamol during pregnancy are generally in a worse state of health than those who do not. For example, they may have an infection or a chronic disease. It is possible that the infection or chronic disease has an influence on the development of autism, and the researcher may think that this is a direct correlation between paracetamol and autism. Although scientists try to account for such variables in their studies, this is often not enough, especially when it comes to an over-the-counter drug in most countries. It is doubly difficult to establish a causal link.
If the risk were confirmed, what realistic regulatory steps could be taken to restrict paracetamol use?
If the risk were confirmed with solid evidence, and if it were found that the risk of paracetamol outweighs the risks of fever to the fetus in pregnant women, then a pregnant woman should only take paracetamol in extreme cases. However, existing studies, including those that have found an association between paracetamol and autism, also note that the risks of paracetamol are much smaller than the risks of a prolonged fever in pregnant women. Paracetamol is the only pain reliever that is not contraindicated for pregnant women, and there is not enough evidence at this stage to restrict it.
