Paracetamol (acetaminophen) is a drug widely used during pregnancy. A new study finds that the drug has a strong link to autism spectrum symptoms in male newborns and for both male and female babies in terms of hyperactivity and attention-related indicators.
When compared to children not exposed to paracetamol during infancy, findings showed a 30 percent increased risk in terms of damage to several attention functions. The link also carried an increased risk in the development of autism spectrum symptoms' two clinical signs among young boys.
For the study, Spanish researchers analyzed 2,644 pairs of mother and child. About 88 percent of the children underwent evaluations when they reached their first year, while 79.9 were screened when they were 5 years old.
The mothers answered questions about their paracetamol usage during their pregnancies. The mothers were not able to recall the exact amounts they took. The researchers noted that the mothers either never used paracetamol, used it irregularly or took them persistently.
The team found that the children aged 1 (43 percent) and aged 5 (41 percent) were exposed to paracetamol at some point within the mothers' first 32 weeks of pregnancy. When the children were evaluated at the latter age, they carried even higher risks of developing impulsivity or hyperactivity symptoms.
The children who were persistently exposed to the drug during pregnancy showed worse performance on computer-based tests that measured visual speed processing, impulsivity and inattention.
The boys who were persistently exposed to the drug during their mothers' pregnancies also showed more symptoms of autism spectrum.
According to study co-author Dr. Jordi Julvez, paracetamol poses harm to the neurodevelopment for various reasons. One of these reasons is that the drug relieves pain by acting on the brains' cannabinoid receptors.
These receptors play a role in determining not only how neurons develop but also how they connect with each other. The drug can affect these vital brain processes. Paracetamol can also impact the immune system's development or become toxic to the fetuses, as they do not have the same ability to metabolize the drug as adults would.
"Although we measured symptoms and not diagnoses, an increase in the number of symptoms that a child has, can affect him or her, even if they are not severe enough to warrant a clinical diagnosis of a neurodevelopmental disorder," said lead author and CREAL researcher Claudia Avella-Garcia.
The study, which was published in the International Journal of Epidemiology journal on July 1, is the first of its kind to show an independent link between paracetamol usage and children's autism spectrum symptoms.