Acetaminophen taken during pregnancy may be linked to the development of attention deficit hyperactivity disorder (ADHD) in children, according to a preliminary study from Denmark.
Experts say the study does not prove a cause-and-effect relationship and more research is needed. It is likely to prompt concerns among women who were told Tylenol and other acetaminophen-based drugs are safe during pregnancy.
The study examined the medical records of more than 64,000 Danish children born from 1996 to 2002. The researchers looked for a possible link between acetaminophen and ADHD because they believe the drug may be a hormone disruptor capable of affecting fetal brain development. Researchers tracked children through questionnaires parents completed when children were 7 years old as well as diagnoses of “high-end” ADHD called hyperkinetic disorder, and ADHD medication prescriptions.
The study found that children whose mothers took acetaminophen during pregnancy were:
- 13 percent more likely to show behaviors associated with ADHD
- 37 percent more likely to be diagnosed with hyperkinetic disorder
- 29 percent more likely to be prescribed ADHD medication
The associations held up even when researchers considered mothers’ mental health histories and the factors that might have led them to take acetaminophen in the first place. The correlation was stronger the more mothers reported taking acetaminophen.
The study “should be interpreted cautiously and should not change practice,” says an accompanying editorial written by psychiatric researcher Miriam Cooper and colleagues at Cardiff University in the United Kingdom. But the findings “underline the importance of not taking a drug’s safety during pregnancy for granted.”
Pregnant women should consult with their physicians before starting or stopping any medication.