Recent medical studies have determined using high doses of Tylenol (or generic acetaminophen) during pregnancy may cause an increased risk of having a baby with autism spectrum disorder. The new research regarding the link between Tylenol use during pregnancy and autism has prompted many parents of autistic children to bring product liability lawsuits against manufacturers and retailers of acetaminophen products.
Tylenol is the iconic brand name for a drug called acetaminophen. Tylenol is one of the world’s most popular and commonly used over-the-counter pain relief medications. Over 95% of the adult population in the United States has used Tylenol or a generic acetaminophen product at some point. It is estimated that around 1/3 of the U.S. population (over 100 million people) uses acetaminophen products on a weekly basis.
In a 2018 meta-analysis of several studies, researchers found that pregnant individuals who took Tylenol over an extended period had a 20% higher risk of autism and a 30% higher risk of ADHD in their unborn children.
Researchers at Johns Hopkins measured the volume of acetaminophen in the blood of newborn children. They found a correlation between the amount of acetaminophen in the blood and the increased likelihood of being diagnosed with ASD or ADHD.
Doctors from across the world signed a joint consensus statement that stated that pregnant people should forgo the use of acetaminophen completely unless administered by a doctor and the individual is closely monitored – all due to the neurodevelopmental effects of acetaminophen on the unborn. The Consensus Statement outlined the significant epidemiological research and testing showing an association between prenatal exposure to acetaminophen abnormalities in fetal development, causing higher rates of neurodevelopmental disorders such as autism. 29 observational studies including over 220,000 mother-child pairs from across the world, were cited in the Consensus Statement.
These articles repeatedly found a causal connection between high acetaminophen use during pregnancy and higher-than-average rates of autism spectrum disorder. As a whole, the studies in these articles found that high-dose use of Tylenol during pregnancy increased a baby’s risk of autism by 20%.
The Consensus Statement strongly recommended that the medical community take precautionary actions to warn about the potential risks of using Tylenol during pregnancy. One of the recommendations included a warning label on all acetaminophen products about use during pregnancy.
This call to action followed more than ten years of scientific research, which included twenty-six epidemiological studies that established positive associations between acetaminophen use during pregnancy and ASD or ADHD.
Sixteen of those studies specifically examined dose-response associations, all finding that a higher duration of exposure to acetaminophen correlated with an increased risk. Beyond formal epidemiological studies, a 2020 study published in JAMA Psychiatry found that biomarkers of fetal exposure to acetaminophen through the umbilical cord were linked to a significantly higher risk of childhood ADHD and ASD in a dose-response manner.
The authors noted that the consistent associations between acetaminophen and ADHD or ASD held true across several potential confounders, such as maternal indication, substance use, preterm birth, and child age and sex. The authors concluded that their findings reinforced previous research regarding the association between prenatal and perinatal acetaminophen exposure and neurodevelopmental risks in childhood.