Children whose mothers used Tylenol during pregnancy may face a higher risk of developing ADHD and autism, according to the findings of a new study.
In a study published this week in the medical journal JAMA Psychiatry, Johns Hopkins University researchers report that children with the highest levels of acetaminophen metabolites in their cord blood at the time of birth have a higher risk of developmental disorders.
Researchers studied 996 mother-infant pairs from the Boston Birth Cohort who were enrolled at birth and followed up at the Boston Medical Center from October 1, 1998, to June 30, 2018. The Boston Birth Cohort only includes babies who were single births, were not conceived with in vitro fertilization, and were born without major birth defects
Three cord blood acetaminophen metabolites were measured in each infant umbilical cord plasma sample collected at birth.
One-quarter of children were diagnosed with attention-deficit hyperactivity disorder (ADHD), 6% were diagnosed with Autism spectrum disorder only, 4% were diagnosed with both ADHD and Autism, and 30% of children were diagnosed with other developmental disabilities. One-third of children had normal neurodevelopment with no disabilities.
All of the cord blood samples contained some detectable levels of acetaminophen metabolites. However, cord blood biomarkers and fetal exposure to acetaminophen were linked with significantly increased risk of childhood ADHD and autism.
When researchers compared the children with the highest levels of acetaminophen in the cord blood samples to those with the lowest levels, children with the highest levels were more likely to have neurodevelopment disorders. Those children were nearly three times as likely to have been diagnosed with ADHD and nearly four times as likely to have autism.
Autism spectrum disorder is a developmental disability characterized by problems with social interactions and communication. Children with autism often complete repetitive and restrictive behaviors. New research indicates the number of children being diagnosed with autism is increasing, with one in every 59 children now on the spectrum.
ADHD is a brain disorder that can affect daily function and can cause inattention, hyperactivity, and impulsivity.
Tylenol, also known generically as acetaminophen, lingers in the system. Researchers were able to estimate maternal acetaminophen use before delivery. However, because the levels were measured at birth, it doesn’t indicate long-term exposure throughout the pregnancy. Researchers can’t say how often the mother’s took Tylenol or at what points during pregnancy.
The study did have its limitations. Researchers couldn’t distinguish whether the higher risk of developmental disabilities is from the acetaminophen use or from the reason a mother was using it to begin with. For example, if a mother was sick and had a high fever or some type of infection, which could affect the fetus.
The researchers said their study appears to corroborate previous findings by other researchers. One recent study published in January 2018 linked Tylenol use to language delays in girls.
In that study, published in European Psychiatry, girls whose mothers took more than six acetaminophen tablets were nearly six times more likely to suffer language delays, the researchers determined. Girls whose mothers urinary concentrations of acetaminophen were highest were more than 10 times more likely to suffer language delays than the urinary concentration of girls whose mothers’ concentrations were the lowest, the findings indicate.
“Our findings support previous studies regarding the association between prenatal and perinatal acetaminophen exposure and childhood neurodevelopmental risk and warrant additional investigations,” study authors wrote.