An epidemiological study of more than 70,000 children has linked symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum conditions (ASC) to the mothers’ use of paracetamol (acetaminophen) during pregnancy.
The study, published in the European Journal of Epidemiology, was led by the Barcelona Institute for Global Health (ISGlobal), a center supported by the “la Caixa” Foundation.
The researchers analyzed a total of 73,881 children for whom data were available on prenatal or postnatal exposure to paracetamol, at least one symptom of Autistic Spectrum Disorder (ASD) or ADHD, and main covariates.
Between 14 percent and 56 percent of the mothers reported taking paracetamol while pregnant.
The study found that children exposed to paracetamol before birth were 19 percent more likely to develop ASD symptoms and 21 percent more likely to develop ADHD symptoms than children who were not exposed.
“We also found that prenatal exposure to paracetamol affects boys and girls in a similar way, as we observed practically no differences.”
“Our findings are consistent with previous research,” said ISGlobal researcher Sílvia Alemany, lead author of the study.
“Our results address some of the weaknesses of previous meta-analyses,” added Jordi Sunyer, researcher at ISGlobal and last author of the study.
“Considering all the evidence on the use of paracetamol and neurological development, we agree with previous recommendations indicating that while paracetamol should not be suppressed in pregnant women or children, it should be used only when necessary.”
An estimated 46 percent to 56 percent of pregnant women in developed countries use paracetamol at some point in their pregnancies. Paracetamol is considered the safest analgesic/antipyretic for pregnant women and children. However, mounting evidence has linked prenatal paracetamol exposure to poorer cognitive performance, more behavioral problems, and ASD and ADHD symptoms.
Those previous studies have been criticized for their heterogeneity, the researchers said.
The current study also analyzed postnatal exposure to paracetamol and found no association between paracetamol use during childhood and ASD symptoms.
“The sample is large,” Alemany added, “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.”
Nevertheless, the research team concluded that further studies are needed, given the heterogeneity of postnatal paracetamol exposure among the various cohorts, which ranged from six percent to 92.8 percent.
Paracetamol, or acetaminophen as it is called in the United States, is used by 52 million Americans each week; it is also found as a component of more than 600 different medications, over-the-counter and prescription strength, according to the Consumer Healthcare Products Association.