Does Tylenol Cause Autism? Acetaminophen Linked to Autism Spectrum Disorder

June 20, 2023 | Attorney, Matthew Dolman
Does Tylenol Cause Autism? Acetaminophen Linked to Autism Spectrum Disorder

Does Tylenol cause autism? Tylenol use (or the use of generic acetaminophen) by pregnant women has now been the subject of over twenty-six epidemiological studies. All twenty-six studies found an association between their child's in-utero exposure to acetaminophen (commonly sold under the brand name Tylenol) and the diagnosis of autism spectrum disorder or ADHD (attention deficit hyperactivity disorder) in the baby who was exposed.

In September 2021, a consensus statement signed by ninety-one scientists appeared in the medical journal Nature Reviews Endocrinology. That statement called for pregnant women to exercise precautions in acetaminophen use during pregnancy. The families of children diagnosed with autism after their mothers used acetaminophen during pregnancy are now involved in a nationwide Tylenol autism lawsuit to hold the manufacturers and retailers responsible.

In this article, we will discuss the body of scientific evidence and emerging research linking pregnant mothers' use of Tylenol and autism spectrum disorder (ASD) diagnoses in their children.

(**Please note the Food and Drug Administration (FDA) has not formally reviewed recent studies concerning in-utero Tylenol exposure. In fact, the last time the FDA formally reviewed scientific data concerning this link was back in 2016.)

The Tylenol Autism Connection: Acetaminophen Exposure During Pregnancy Linked to Heightened Risk of Autism

A reported 70% of pregnant women use acetaminophen products during pregnancy for pain relief or fever reduction. Acetaminophen is an active ingredient in over 600 medications, including the following:

  • Alka-Seltzer Plus,
  • Actifed,
  • Cepacol,
  • DayQuil,
  • Excedrin,
  • Mucinex,
  • NyQuil,
  • Robitussin,
  • Sudafed, and
  • Tylenol.

We now have a body of science that provides compelling evidence this common pain reliever can pose danger to a developing fetus and has commonly been associated with adverse and complex developmental disorder conditions, including Tylenol causing autism or ADHD.

How Much Tylenol Is Safe During Pregnancy?

The specific usage amounts of Tylenol linked to autism have yet to be determined.  There have been two studies that demonstrate a dose-dependent relationship - in other words, the greater the levels of acetaminophen exposure, the greater the rate of autism. Currently, there are no guidelines or guidance on what level of acetaminophen is safe during pregnancy.  

Several of the leading researchers speculate that the occasional use of acetaminophen is not dangerous. However, consistent prenatal acetaminophen exposure is considered a potential cause of autism. More research must be conducted about what constitutes safe levels of acetaminophen exposure.

We will explore all previous studies on the use of acetaminophen during pregnancy linked to autism and other developmental disorders. We will also analyze a number of previous studies within the context of fetal exposure to acetaminophen. Please note the science may actually be even stronger in the context of risk for attention deficit hyperactivity disorder (ADHD).

Will the FDA Weigh in on Whether the Manufacturers and Retailers Should Warn About Tylenol and Autism or ADHD?

In an unusual move, the Judge who is overseeing the Tylenol multidistrict litigation sent two questions to the Food and Drug Administration in May 2023:

  1. Whether acetaminophen products should carry the proposed warning suggested by the plaintiffs' counsel?
  2. Whether the current scientific studies warrant adding a label to warn about acetaminophen use while pregnant and the risk of ASD or ADHD?

Considering the outcome of one of the biggest mass torts in history may hinge on these questions, we will be surprised if the FDA answers. On one hand, if the FDA answers, there is a chance that they may say that they would never have approved any labeling warning of ADHD or ASD, which would negatively affect the injured plaintiffs' claims. However, it is significantly more likely that they will simply refuse to respond, which could benefit the plaintiffs in this litigation.

The FDA has been reluctant to weigh in on this issue earlier in the litigation when Johnson & Johnson filed a motion to dismiss the lawsuit. Put simply, the FDA was concerned that a warning would generate panic among consumers since there would be no safe over-the-counter pain relievers available for use by women during pregnancy.

Time will tell how the FDA chooses or does not choose to respond, which is why we are paying careful attention to any developments.

Scientists Ask: Does Tylenol Cause Autism? A Review of the Medical Studies Showing Tylenol Linked to Autism Spectrum Disorder and ADHD

Tylenol Autism Consensus Statement Signed by 91 Scientists and Physicians

A consensus statement issued in 2021 was essentially a call to action as researchers could no longer ignore the overwhelming scientific evidence indicating acetaminophen use during pregnancy could cause autism spectrum disorder or attention deficit hyperactivity disorder (ADHD).

The authors stated, “The combined weight of animal and human scientific evidence is strong enough for pregnant women to be cautioned by health professionals against its indiscriminate use, both as a single ingredient and in combination with other medications.” Additionally, the authors stated, "We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP (acetaminophen) unless its use is medically indicated and minimize exposure by using the lowest effective dose for the shortest possible time."

The use of acetaminophen during pregnancy is an issue that has not received proper attention despite consistent positive associations demonstrated in study after study. This may have something to do with the anti-vaccine movement and the discredited and debunked science behind the vaccine-autism link. We fear the related stigma has resulted in a lack of attention to the danger of regular acetaminophen exposure during pregnancy.

Acetaminophen has long been considered safe to use during pregnancy and is the active ingredient in hundreds of medications. In fact, acetaminophen has been shown to be effective in treating minor to moderate pain as well as low-grade fever.

However, emerging research across twenty-six epidemiological studies and numerous animal studies demonstrates what many researchers believe to be strong evidence of a causal link between in-utero acetaminophen exposure and autism spectrum disorder (ASD).

Prenatal Tylenol Use Poses a Large Risk - Can Prenatal Use of Tylenol Cause Autism?

The authors of the consensus statement on acetaminophen and autism believe that prenatal acetaminophen exposure and perinatal use or exposure can negatively impact fetal brain development. In fact, the writers state, “consistent with the epidemiological data, studies have demonstrated that the strongest effects of long-term use and exposure occur at a time equivalent to the beginning of the third trimester of pregnancy and the time around birth in humans.”

Finally, the authors state, “We as a society should be able to take protective action when scientific evidence indicates a chemical is of concern, and not wait for unequivocal proof that a chemical is causing harm to our children. Evidence of neurodevelopmental toxicity of any type — epidemiological or toxicological or mechanistic — by itself should constitute a signal sufficient to trigger prioritization and some level of action.”

Again, researchers' main concern is the adverse impact of acetaminophen on fetal brain development. A medical body containing strong evidence, consisting of a decade's worth of studies linking Tylenol to autism and child development, was no longer something to be ignored. Further, new scientific research discussed in this article only increases the confidence of researchers concerning the link between Tylenol and autism. The risks of acetaminophen use by pregnant women is simply too strong to ignore.  Prenatal acetaminophen exposure has been shown time after time to result in an adverse impact on fetal brain development and an increased risk for a child with autism.

The scientists who penned this study referenced that the use of acetaminophen may be necessary for pregnant women in specific situations. However, they cautioned that using generic acetaminophen products or Tylenol regularly as opposed to brief instances is what concerned them.

In other words, the authors stressed that obstetricians should counsel pregnant women that the use of acetaminophen products during pregnancy should be for as brief a period of time as possible at the lowest possible dosage. Obstetricians would be wise to advise their patients of the link between acetaminophen use and autism as well.

Finally, the authors cautioned that more research needs to be conducted as to what would constitute a safe dose of acetaminophen or the appropriate levels of acetaminophen exposure for a pregnant woman and her unborn child.

European Journal of Epidemiology (2021) - A Statistical Connection Between Tylenol and Autism Diagnoses

Researchers analyzed data from 73,881 children via six previous birth cohort studies. This study on prenatal and postnatal exposure to acetaminophen appeared in the European Journal of Epidemiology. The analyses of the studies demonstrated that children with prenatal exposure to Tylenol/acetaminophen had a statistically significant increase in the diagnosis of autism spectrum disorder and ADHD.

This study showed a clear link between the use of acetaminophen by pregnant women and a child's risk for autism spectrum disorder and/or ADHD diagnosis. This is yet another study finding acetaminophen use during pregnancy is associated with Autism Spectrum Disorder, and a baby's in-utero exposure to acetaminophen has been shown to be associated with ASD.

An important distinction to be made is the researchers did not find any association between postnatal generic acetaminophen exposure and autism or ADHD. The findings of an increased rate and risk of autism spectrum disorder and ADHD were consistent only for prenatal use of acetaminophen.

Johns Hopkins University Boston Birth Cohort (2019) - Higher Amounts of Acetaminophen in Umbilical Blood Lead to a Higher Incidence of ASD

2019 study published in the scientific journal JAMA Psychiatry found cord biomarkers (umbilical cord blood samples) of fetal acetaminophen exposure were associated with a significantly increased rate of autism spectrum disorder and ADHD in a “dose-response fashion.” In other words, the greater the amount of acetaminophen found within umbilical cord blood samples, the greater the incidence rate of autism spectrum disorder or ADHD diagnosis. This is known as the Johns Hopkins University Boston Birth Cohort study, and it adds greater credence to the claim that regular use of Tylenol while pregnant could present problems.

If nothing else, the Johns Hopkins University Bloomberg School of Public Health study established that in-utero exposure to acetaminophen increased a child's risk for autism spectrum disorder and attention deficit hyperactivity disorder, as well as other neurodevelopmental disorders.

This was a twenty-year study of pregnant women and the early life factors of their children. The researchers measured biomarkers for acetaminophen levels within the umbilical cord blood samples in 996 separate births.

Babies with the highest level of acetaminophen in their umbilical cord blood samples (found in cord plasma acetaminophen metabolites) were three times more likely to be diagnosed with Autism Spectrum Disorder or ADHD later on in life as compared to infants with the lowest level of acetaminophen.

Additionally, researchers found a consistent association between acetaminophen levels found within biomarkers of cord blood samples and autism spectrum disorder and ADHD across a number of confounding factors, including preterm birth, substance abuse, smoking, maternal stressors, and maternal BMI. The dose-response findings support the working theory that Tylenol adversely impacts fetal development. In fact, we believe this is strong evidence of a causal connection with adverse neurodevelopmental outcomes. This is the first study that demonstrated a dose-dependent association between acetaminophen exposure and autism.

The lone criticism of this study is researchers had to rely on the mothers' self-reporting, which is not always ideal. There are ethical reasons that pose a limitation to scientists performing more than observational studies on pregnant women. It would be unethical to purposely subject pregnant women to a known health risk.

Recall bias and no objective measures for tracking in-utero exposure to acetaminophen during specific periods of pregnancy are the lone drawbacks to this particular study. In other words, there was no specific method to track exactly how much acetaminophen a pregnant woman took during her pregnancy. It is crucial to view these studies in their totality as a cumulative body of science.

Acetaminophen Use in Pregnancy and Neurodevelopment (2016) - A Clear Connection Between Tylenol and Autism

In a 2016 study published in the International Journal of Epidemiology, researchers analyzed 2644 mother-child pairs. They analyzed children at ages one and five to determine whether prenatal exposure to acetaminophen led to an increased risk for autism spectrum disorder or ADHD by measuring clinical symptoms. Researchers found a clear connection and increased risk between Tylenol use during pregnancy and autism.

This study was unique in finding an association between Tylenol use and autism dependent on the frequency of exposure to acetaminophen during pregnancy. This finding was repeated with much greater clarity in the aforementioned Johns Hopkins Boston Birth Cohort study, which again showed a dose-response factor based on the overall use of acetaminophen.

Danish National Birth Cohort Study (2015) - Maternal Use of Acetaminophen Analyzed During Pregnancy as a Risk Factor for Autism Spectrum Disorder

Researchers analyzed 64,322 mother-child pairs over 12.7 years to better understand the cause of diseases in children. This study specifically analyzed acetaminophen use during pregnancy to determine whether there was an association with an increased rate of autism spectrum disorder in offspring. This assessment has been utilized in a number of other meta-analyses of existing scientific evidence.

Scientists found that in-utero exposure to acetaminophen had an adverse effect on fetal development and led to a significant increase in diagnosis for ADHD and a notable increase in autism spectrum disorder.

JAMA Psychiatry Study (2014) - Confirms Danish Study

Another research team analyzed the Danish national birth cohort study that was conducted between 1996 – 2002. Scientists again found an increase in both ADHD and hyperkinetic disorder (abnormal involuntary movements), which is a severe form of ADHD following in-utero exposure to Tylenol/acetaminophen exposure

Acetaminophen Exposure and Fetal Brain Development (Yale Study)

Early Reports About the Tylenol-Autism (and Other Neurodevelopmental Disorders) Risks

The Yale University School of Public Health also published the findings echoed by 91 scientists in the previously mentioned consensus statement. Zeyan Liew, Ph.D., M.P.H., professor at the Yale University School of Public Health, states that Yale's lab was among the first to report detrimental effects of acetaminophen use during pregnancy and acetaminophen exposure on fetal brain development.

It is worth noting the authors of the previously referenced consensus statement relied on twenty-five years of epidemiological, animal, and in-vitro studies in arriving at their conclusions. The research team found an increased risk for neurodevelopmental disorders such as autism spectrum disorder, attention deficit hyperactivity disorder, decreased IQ, and language delays. Overall, this common pain reliever is consistently associated with disorders relating to fetal brain development.

Acetaminophen has been shown to cross the placental barrier and is theorized to cause alterations to maternal hormones and detrimentally impact fetal development.

2022 Animal Study of Tylenol Use and Fetal Brain Development

Can Tylenol Cause Autism

Consistent with the totality of animal studies, in Paracetamol (Acetaminophen) and its Effect on the Developing Mouse Brain, researchers found that mice exposed to relevant doses of acetaminophen (meant to mimic regular use of Tylenol as opposed to mere occasional use) displayed reduced memory and learning ability and other signs of neurodevelopmental disorders. It appeared to the scientists that Tylenol induces oxidative stress in the hippocampus, which likely plays a large role in the manifestation of neurodevelopmental issues.

The question remains; what pain relievers will pregnant women have available in the future? Among all pain relievers, and with limited medical alternatives, Tylenol has long been thought to be safe for consumption by pregnant women.

Clearly, more research must be conducted in this area for the safety of pregnant women and their children. However, maternal use of acetaminophen products poses a higher risk for neurodevelopmental disorders such as autism. The studies clearly demonstrate children exposed to environmental conditions in-utero and perinatal, along with genetic factors, pose serious risk factors for the potential to develop autism.

Please note that we are NOT stating that Tylenol causes autism. Rather, we believe that the regular use of Tylenol by pregnant women throughout large periods of pregnancy poses an increased risk of a child subsequently being diagnosed with Autism Spectrum Disorder. We believe it is “a cause” as opposed to “the cause.”

Our Tylenol autism lawyers are currently taking clients with children that have developed health issues related to exposure to acetaminophen while in the womb. Dolman Law Group is a personal injury law firm that provides award-winning legal representation to those harmed by defective medical products. Contact us today for a free consultation to learn how we can help you.

Most Recent Study Shows Tylenol Linked to Autism Without Controversy

A study completed in October of 2022 that is in the process of being peer-reviewed sheds the latest light on the link between Tylenol use during pregnancy and autism along with other neurodevelopmental injuries. The study is entitled Acetaminophen Causes Neurodevelopmental Injury in Susceptible Babies and Children: No Valid Rationale for Controversy. This is the first study that reviews and evaluates confounding factors for autism within the context of all prior studies on this subject to date.  Further, the authors tackle the specific criticisms of this body of scientific data within the overarching existing controversy of whether in-utero exposure to acetaminophen causes autism. 

Critics of the acetaminophen autism link argue the rapidly climbing rates of ASD in the pediatric population are attributed to improved diagnostic criteria and awareness.  However, a careful analysis of all existing data and, more specifically, disparities between rates of autism measured in multiple birth cohort studies can only be explained by the role of an environmental factor such as a chemical.

Another common argument pushed by both critics of the science along with the manufacturers and retailers of generic acetaminophen and Tylenol is correlation does not equate to causation. Of course, no scientific study is perfect. And this issue is complicated by the ethical concerns of studying pregnant women.  

Scientists cannot ethically provide medication or chemicals known to be dangerous to mothers and unborn children.  This is why researchers are so reliant on observational data and why it is so essential to look at the entire body of science, including the studies of acetaminophen on pregnant animals.  

Multiple animal studies found that in-utero exposure to acetaminophen inhibited fetal brain development.  It is also worth noting that the animals studied were not using acetaminophen to treat medical issues such as a fever. Fever during pregnancy is a confounder (or confounding variable) for the risk of autism. Lastly, every study of pregnant women or fetal exposure demonstrated positive associations between acetaminophen and autism.

Finally, the authors conclude that after reviewing a number of potential confounders (including bias of participants) and criticisms of the science, there is a valid rationale for the conclusion that in-utero exposure to acetaminophen causes neurodevelopmental injuries such as autism spectrum disorder. Additionally, the authors discuss the mechanism of injury (how acetaminophen causes neurodevelopmental injury), which includes an increase in oxidative stress.  Increased oxidative stress levels increase the risk of autism and are consistently associated with neurodevelopmental injuries in a wide array of previous studies.

Visit this page for the latest news in autism litigation and the Tylenol autism lawsuit.

Dolman Law Group Has Extensive Experience with the Tylenol Autism Lawsuits

Tylenol Cause Autism

Our law firm began investigating claims relating to the link between using acetaminophen while pregnant and autism spectrum disorder last summer. We were one of the first law firms involved, and we now represent nearly 1,000 clients with claims or Tylenol autism lawsuits against the manufacturers of Tylenol (Johnson & Johnson) and generic acetaminophen products. Further, we are also a part of the legal team with claims or lawsuits against retailers such as CVS, Walmart, Walgreens, Costco, and others for failing to warn pregnant women about the dangers of consuming acetaminophen during pregnancy and the risks it may pose to a developing fetus.

We are presently representing numerous mothers in federal multidistrict litigation. This is where all lawsuits that are filed in federal courts throughout the nation alleging Tylenol or its generic version caused autism/ADHD have been consolidated in one venue before Judge Denise Cote in the Southern District of New York. 

Call Dolman Law Group to Answer Your Questions and Handle Your Infant Tylenol Autism Lawsuit

If you have a child diagnosed with Autism Spectrum Disorder or ADHD and you used acetaminophen products during your pregnancy, please contact us immediately. Our attorneys offer a free consultation and case review to determine whether you are qualified. The Dolman Law Group actively represents injured consumers in product liability lawsuits,  mass tort cases, and mass tort litigation. Along with the toxic baby food autism lawsuit, will continue playing a role in the national Tylenol autism lawsuit.

For more information, feel free to check this website for regular Tylenol autism lawsuit updates:


Matthew Dolman

Personal Injury Lawyer

This article was written and reviewed by Matthew Dolman. Matt has been a practicing civil trial, personal injury, products liability, and mass tort lawyer since 2004. He has successfully fought for more than 11,000 injured clients and acted as lead counsel in more than 1,000 lawsuits. Always on the cutting edge of personal injury law, Matt is actively engaged in complex legal matters, including Suboxone, AFFF, and Ozempic lawsuits.  Matt is a lifetime member of the Million Dollar Advocates Forum and Multi-Million Dollar Advocates Forum for resolving individual cases in excess of $1 million and $2 million, respectively. He has also been selected by his colleagues as a Florida Superlawyer and as a member of Florida’s Legal Elite on multiple occasions. Further, Matt has been quoted in the media numerous times and is a sought-after speaker on a variety of legal issues and topics.

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