A quarterly publication of the Autism Research Institute
Summer, 2021 | Number 3, Volume 35
Prenatal exposure to acetaminophen (the active ingredient in Tylenol) may raise children’s risk for autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD), according to a large-scale study.
Silvia Alemany and colleagues analyzed data on 73,881 children in six different European birth cohorts. The researchers controlled for a range of maternal variables including age and education, body mass index, use of alcohol or tobacco, mental health problems, number of pregnancies, and fever or infections during pregnancy. In addition, they controlled for variables involving the children, including sex, age, and occurrence of colds and respiratory infections during the first two years of life.
The researchers found that children exposed to acetaminophen before birth were 19% more likely to develop symptoms of ASD and 21% more likely to develop symptoms of ADHD than children who were not exposed. The findings were similar for boys and girls. The researchers found no increased risk related to children’s exposure to acetaminophen after birth.
Two previous meta-analyses also pointed to an association between acetaminophen and autism or ADHD, but they were criticized because of the heterogeneity of the studies the meta-analyses reviewed. The new study, Alemany says, addresses these concerns. “The sample is large,” she says, “and it includes cohorts from multiple European countries: the United Kingdom, Denmark, the Netherlands, Italy, Greece and Spain. We also used the same criteria for all of the cohorts, thereby reducing the heterogeneity of criteria that has hampered previous studies.”
The researchers conclude, “[W]e agree with previous recommendations indicating that while acetaminophen should not be suppressed in pregnant women or children, it should be used only when necessary.”
“Prenatal and postnatal exposure to acetaminophen in relation to autism spectrum and attention-deficit and hyperactivity symptoms in childhood: Meta-analysis in six European population-based cohorts,” Silvia Alemany, Claudia Avella-García, Zeyan Liew, Raquel García-Esteban, Kosuke Inoue, Tim Cadman, Mònica López-Vicente, Llúcia González, Isolina Riaño Galán, Ainara Andiarena, Maribel Casas, Katerina Margetaki, Katrine Strandberg-Larsen, Deborah A. Lawlor, Hanan El Marroun, Henning Tiemeier, Carmen Iñiguez, Adonina Tardón, Loreto Santa-Marina, Jordi Júlvez, Daniela Porta, Leda Chatzi, and Jordi Sunyer, European Journal of Epidemiology, May 28, 2021 (free online). Address: Silvia Alemany, [email protected].
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“Prenatal exposure to acetaminophen associated with ADHD and autism,” news release, Barcelona Institute for Global Health, May 28, 2021
