Researchers link acetaminophen use during pregnancy with higher risk of behavioral problems such as attention-deficit/hyperactivity disorder (ADHD)-like symptoms in babies.

The over-the-counter pain relievers might increase risk of a severe form of ADHD called hyperkinetic disorders.

Acetaminophen (Tylenol or paracetamol) belongs to a category of drugs called analgesics and is used to treat mild pain, cramps, cold and sore throat. The drug, when used in recommended dosage, is considered safe for pregnant women.

"Maternal acetaminophen use during pregnancy is associated with a higher risk for HKDs and ADHD-like behaviors in children. Because the exposure and outcomes are frequent, these results are of public health relevance but further investigations are needed," the study authors wrote, according to a news release.

The study was conducted by researchers at University of California, Los Angeles and University of Aarhus in Denmark. It was based on data from 64,322 children and mothers in the Danish National Birth Cohort (1996-2002)study. Researchers obtained information about ADHD/ HKD diagnoses from Danish registries. Parents were asked to answer the Strength and Difficulties Questionnaires, which assess behavioral problems in children.

Data analysis showed that over half of the mothers in the study used acetaminophen during pregnancy. Researchers found that the drug use was associated with higher risk of HKD and ADHD-like symptoms, according to a news release.

But don't throw away the pain-reliever yet. Experts say that the latest study found a preliminary link between acetaminophen and ADHD-like behaviors in children. Further research is needed to confirm the association.

"In summary, findings from this study should be interpreted cautiously and should not change practice. However, they underline the importance of not taking a drug's safety during pregnancy for granted, and they provide a platform from which to conduct further related analyses exploring a potential relationship between acetaminophen use and altered neurodevelopment," Miriam Cooper, of Cardiff University School of Medicine, Wales, and colleagues wrote in an editorial accompanying the study.

People with ADHD or Attention-Deficit / Hyperactivity Disorder have poor attention spans and have problems controlling behavior.

The study is published in the Journal of the American Medical Association Pediatrics.