Tag: autism

Acetaminophen, Pregnancy, and Neurodevelopment: What the Science Really Says

Acetaminophen, more commonly recognized by the brand name Tylenol, has been recommended by physicians to pregnant women as a safe fever-reducer and effective pain-reliever for decades. However, in September of this year, President Donald Trump and U.S. Health and Human Services Secretary Robert F. Kennedy Jr. issued a warning regarding a supposed link between Tylenol use during pregnancy and an increased risk of autism in children. These warnings have received massive media attention and spread rapidly across social media platforms, but the scientific evidence behind these claims remains far from conclusive.

The warnings and statements presented by President Trump and Secretary Kennedy risk confusing the public by blurring the crucial distinction between correlation and causation. Correlation merely suggests that two variables are related in some way, while causation indicates that a change in one variable directly causes a change in the other. The difference may sound subtle, but in science and law it is fundamental. Correlation alone is insufficient to prove a cause-and-effect relationship, as other confounding variables may be present. The studies cited by President Trump and Secretary Kennedy merely demonstrate correlation; none provide credible evidence that Tylenol use during pregnancy causes autism in children.

A comprehensive review of 46 studies investigating the relationship between Tylenol use during pregnancy and neurodevelopmental disorders found that more than half showed only minimal associations, while the remainder showed no evidence of increased risk whatsoever. In another large-scale Swedish study involving 2,480,797 children born from 1995 to 2019,  researchers found no statistically significant link between prenatal Tylenol use and autism in children. Additionally, the U.S. Food and Drug Administration (FDA) has reiterated that no causal relationship has been established between Tylenol and neurodevelopmental disorders.

Despite this, President Trump has gone so far as to advise pregnant women to “tough it out” and avoid Tylenol entirely. Yet Tylenol is commonly taken for fever and pain, both of which can pose serious health risks if left untreated. In fact, research suggests that untreated fever during pregnancy may increase the risk for autism in the child as much as forty percent in the second trimester, and more than 300 percent for pregnant women who reported three or more fevers after the twelfth week of pregnancy.

Discouraging pregnant women from using Tylenol, the only over-the-counter pain-reliever approved to use while pregnant, could increase health risks for both mothers and their unborn children. Without access to safe fever and pain management, women may turn to unsafe alternatives or endure conditions that themselves elevate the risk of poor health and pregnancy outcomes.

From a legal perspective, the warnings presented by President Trump and Secretary Kennedy raise significant concerns. The FDA has initiated a process to update the labeling of products containing Tylenol in response to the claims of a potential association between pregnancy use and neurodevelopmental disorders, despite the lack of evidence establishing causation. Manufacturers of Tylenol could be exposed to product-liability litigation because the label change process shifts the standard of care and opens the door to claims of inadequate warnings or information. Additionally, when a highly influential public figure advises pregnant women to “tough it out” and avoid the only approved over-the-counter pain-reliever for use in pregnancy, healthcare providers could face increased exposure to malpractice claims if fever or pain in pregnancy is left untreated and injury results. The discourse created by the warnings from President Trump risks generating confusion among pregnant women about safe Tylenol use, which may lead to under-treatment of fever or pain or even to the substitution of Tylenol with less safe alternatives, increasing potential legal exposure across providers, insurers, and manufacturers.

As of now, both the FDA and the Centers for Disease Control (CDC) continue to advise that acetaminophen remains the safest and most effective over-the-counter pain relief option for pregnant women.

The Trump Administration Issues Inconsistent Guidance Regarding Acetaminophen and Autism

The current presidential administration has placed significant focus on addressing a cited increase in the rate of autism diagnoses. Late last month, President Trump, alongside the Health Secretary, Robert F. Kennedy Jr., issued new health guidance and announced in a press conference that there is evidence of a link between the use of acetaminophen during pregnancy and neurological effects, specifically autism and attention-deficit/hyperactivity disorder (ADHD), in children post-birth. The announcement was coupled with a notice from the U.S. Food and Drug Administration (FDA) that it plans to initiate a process for a label change on acetaminophen products to inform consumers of the link, as well as a letter issued by the FDA to physicians about the potential link. The FDA’s letter specifies that “a causal relationship has not been established” between use of the medication and autism, while also asserting that clinicians may want to suggest pregnant people reduce their use of the medication. The issuance of sweeping advice from the Trump Administration in light of these inconsistencies is unsettling from a public health perspective because acetaminophen remains the recommended drug for fever reduction in pregnant people. The guidance to minimize acetaminophen use could be harmful for pregnant people because it may lead them to endure unnecessary pain and fever, which are dangerous for the pregnant person and the fetus.

In addition, mixed messages have created confusion in the legal context because of the announcement’s reliance on a study that was previously found inadmissible by a judge. In 2022, a group of families sued the maker of Tylenol, an acetaminophen product, for failure to warn consumers of the risk that prenatal exposure to the medication may create a heightened risk of autism. One of the experts used to support the families’ proposition was Andrea Baccarelli, MD, PhD, who was also cited in the Trump Administration’s recent announcement. The judge rejected this expert, as well as all of the families’ other experts, in an order in 2023, stating that the experts had “cherry-picked” data in their analyses. The case was subsequently dismissed in 2024, and the dismissal is currently on appeal.

In light of the executive branch’s reliance on one of the same experts as the families, the plaintiffs’ attorney has filed a letter with the court in support of their appeal, noting that the expert had been relied upon in the conclusions of a recent White House briefing. The lawyer notes the separation of power concerns that would arise if the ruling that this expert’s opinions are inadmissible in court is affirmed, while the opinions are simultaneously cited as valid by the executive branch. On the other hand, the attorney for Tylenol in the same lawsuit has also filed his own letter referencing the advice put out by the Trump administration as support of the defendant’s position that they have not failed to include any warning of a link to autism on their products. The defendant’s lawyer cites the language in the FDA’s letter to doctors stating that there is no causal relationship between the drug and autism. In light of each of letters, the judge has pushed back oral argument on this appeal that was set to occur on October 6, 2025 to November 17, 2025.

The use of the Trump administration’s guidance in this litigation to both support and disprove a link between Tylenol and autism emphasizes the confusion the new health guidance has created. What does this mean going forward? In the immediate future, the guidance may create fear among pregnant people about treating their pain and fever during pregnancy. If moving forward, the guidance does successfully ignite litigation aimed at a requirement to label acetaminophen products as not recommended during pregnancy, it could lead to an increase in pregnant people leaving pain and fever untreated during pregnancy, potentially putting them in danger of other complications.