Acetaminophen (Tylenol) might not be safe for unborn babies

A new study published in the JAMA Pediatrics suggests increased use of acetaminophen in pregnancy may increase the risk of ADHD (attention deficit hyperactivity disorder) in the unborn child in later life.1

64,000 children and their moms were studied and it was found that the more acetaminophen the mother took during pregnancy, the greater the risk the child later developed ADHD or a more severe, and normally rare, hyperkinetic disorder (HKD).

Acetaminophen (also known as paracetamol) is the primary ingredient found in Tylenol and many other pain-reliving medications. It has been long thought that acetaminophen was one of the safest pharmaceuticals a pregnant woman could take and is therefore one of the most common pain relievers used during pregnancy.

Biomedical scientists do not currently know if there is a cause-and-effect link between acetaminophen and ADHD and currently there is no plan by the medical community to change recommendations in regards to use during pregnancy.

More than half of women questioned reported to have taken acetaminophen during pregnancy.

Further biomedical research is therefore required to determine if it is the acetaminophen drug itself which is somehow causing an increased risk, and not some other correlating factor (such as the environment which may lead to the need to take an increased amount of pain relief). The results did not appear to be confounded by maternal inflammation or infection (as acetaminophen is commonly used for fever).

Current biomedical research data suggests that acetaminophen is a hormone disrupter which may affect fetal brain development.

The study was epidemiologically-based, meaning they looked at a group of people (mothers) and asked them a series of questions to determine how much acetaminophen was used during pregnancy, whether their child had ADHD or HKD, and whether the incidence increased with increased use.

Researchers found that, in the group of mothers and children up to 7 years of age studied, the more the mothers reported prenatal use of acetaminophen, the greater the odds were that their child had ADHD (50% in crease) or HKD (200% increase).

There was stronger association if acetaminophen was taken beyond the first trimester and for longer than 20 weeks prenatally in total.



Liew Z, Ritz B, Rebordosa C, Lee P, Olsen J. Acetaminophen Use During Pregnancy, Behavioral Problems, and Hyperkinetic Disorders. JAMA Pediatr. 2014.

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