A recent study published in the Journal of the American Medical Association (JAMA) Pediatrics supports growing evidence that the active ingredient in acetaminophen may influence brain development in utero.  Researchers say they have found a strong link between prenatal use of acetaminophen and cases of ADHD (attention deficit hyperactivity disorder) in children.  However, the study does not provide clear answers as to whether acetaminophen is safe during pregnancy.

The study analyzed more than 64,000 Danish women and their children and found that children of mothers who took acetaminophen at any point during the pregnancy were 29% more likely to be diagnosed with ADHD than children whose mothers did not take the medication.  When analyzing which trimester carries the greatest risk the risk was found to increase by 63% when acetaminophen was taken during second and third trimesters and by 28% when taken during the third trimester alone.  The risk was 9% when acetaminophen was only taken during the first trimester.

"Less is Better"

The researchers note that these findings do not establish that prenatal exposure to acetaminophen caused the ADHD; however, they explain that medications are only considered ‘safe’ until studies become sensitive enough to detect subtle problems.  Dr Daniel Kahn; a UCLA obstetrician who was not part of the research says it is best to follow a ‘less is better’ approach and “The lowest exposure is always the best, for any agent.”  Even with these study results Dr Kahn says it would not dissuade him from recommending acetaminophen during pregnancy for a patient with a fever because an untreated fever has been linked to lower IQ in children.

An editorial was published in conjunction with the report cautioning that the findings ‘should be interpreted cautiously’, wrote neuropsychologist Miriam Cooper of the University of Cardiff in Wales.  The editorial cautions physicians and pregnant women should not change their practices based on one study.  The research team had suspected acetaminophen which is known to cross the placental barrier between mother and fetus may behave as an endocrine-disrupting chemical capable of influencing brain development.

The research team was led by Dr Jorn Olsen an epidemiologist at the University of Aarhus in Denmark.  Pediatric subjects were tracked from first trimester of gestation for up to 15 years and used Denmark’s registries of physician diagnoses and dispensed prescriptions to assess an accurate measure of ADHD in the population.  The team will continue to investigate finding to determine if there is further evidence of the neuropsychiatric and other metal health effects of other medications taken during pregnancy.