Startling new findings have thrown into question whether decades of pregnant women taking acetaminophen products such as Tylenol for lower back pain and headaches has led to their children being diagnosed with ADHD.
Kids whose mothers took acetaminophen while pregnant were more likely to develop attention-deficit hyperactivity disorder, a long-term study by UCLA researchers has concluded. The active ingredient in over-the-counter brands such as Tylenol and Excedrin, acetaminophen has long been considered the safest of pain medicines, UCLA reported, and an obstetrician there noted that the underlying condition of the expectant mother would still decide its use.
The researchers followed the cases of thousands of children from in utero to their teen years, and, while not yet directly linking acetaminophen as the cause of ADHD, raise the question of whether pregnant women should take it. The research was published in the online edition of JAMA Pediatrics.
Key Findings:
- The likelihood of a child developing ADHD crippling enough to need medication increased 63% (the most) when the medication was taken during the last two trimesters of a pregnancy.
- When taken only in the third trimester, the ADHD likelihood increased by 28%.
- Interestingly, given there is so much caution about the importance of fetal development in the first trimester, the danger of ADHD was the lowest when pregnant women took acetaminophen only in that first period.
“The causes of ADHD and hyperkinetic disorder are not well understood, but both environmental and genetic factors clearly contribute,” said Dr. Beate Ritz, professor and chairperson of the department of epidemiology at UCLA’s Fielding School of Public Health and one of the senior authors of the paper. “We know there has been a rapid increase in childhood neurodevelopmental disorders, including ADHD, over the past decades, and it’s likely that the rise is not solely attributable to better diagnoses or parental awareness. It’s likely there are environmental components as well.”
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Among the world’s most common neurobehavioral disorders, ADHD has symptoms that include inability to focus attention, increased impulsivity, hyperactivity and impairment in regulating emotions. Hyperkinetic disorder is a very severe form of ADHD. It is most typically treated with prescription stimulant medications such as Ritalin and Adderall. When treated, a combination of drugs and counseling are often used.
Because of the prevalence of ADHD cases and the suspected external factors, the research team zeroed in on the potential connection.
“That gave us the motivation to search for environmental causes that are avoidable,” said the University of Aarhus’ Dr. Jørn Olsen, another senior author and former chair of the UCLA Fielding School’s epidemiology department in an announcement. “Part of the neuropathology may already be present at birth, making exposures during pregnancy and/or infancy of particular interest. Because acetaminophen is the most commonly used medication for pain and fever during pregnancy, it was something we thought we should look at.”
Huge Database
Researchers studied more than 64,300 Danish children and mothers from 1996 to 2002 enrolled in the Danish National Birth Cohort. That huge database examines the country’s pregnancy complications and disease in the children’s younger years with a focus on possible impacts of medicine and infections, UCLA said.
Acetaminophen use during pregnancy was determined using computer-assisted telephone interviews that were conducted up to three times during pregnancy and again six months after childbirth, the report explained.
The researchers next followed up with parents when their children were 7. They first asked parents about any behavioral problems in their children using the Strength and Difficulties Questionnaire, a standard behavioral screening tool used by scientists. It assesses five domains, including emotional symptoms, conduct problems, hyperactivity, peer relationship and social behavior in children and adolescents between the ages of 4 and 16.
The researchers used doctors’ diagnosis of ADHD and records of the drugs prescribed, in this study primarily Ritalin. And they largely ruled out other factors such as inflammation, mental state of the mother.
The potential impact in the U.S. alone is significant given the incidence rate, according to the Centers for Disease Control and Prevention.
- More than one in 10 (11%) U.S. school-aged children had received an ADHD diagnosis by a healthcare provider by 2011, as reported by parents.
- 6.4 million children reported by parents to have received a healthcare provider diagnosis of ADHD, including:
- 1 in 5 high school boys
- 1 in 11 high school girls
- 6.4 million children reported by parents to have received a healthcare provider diagnosis of ADHD, including:
- The percentage of U.S. children 4 to 17 years of age with an ADHD diagnosis by a healthcare provider, as reported by parents, continues to increase.
- A history of ADHD diagnosis by a healthcare provider increased by 42% between 2003 and 2011:
- 7.8% had a diagnosis in 2003
- 9.5% had a diagnosis in 2007
- 11.0% had a diagnosis in 2011
- Average annual increase was about 5% per year
- A history of ADHD diagnosis by a healthcare provider increased by 42% between 2003 and 2011:
- The percentage of children 4 to 17 years of age taking medication for ADHD, as reported by parents, increased by 28% between 2007 and 2011.
- Percentage of children taking medication for ADHD was:
- 4.8% in 2007
- 6.1% in 2011
- Average annual increase was about 7% per year
- Percentage of children taking medication for ADHD was:
Despite the findings and the need for further study, doctors cautioned that going without acetaminophen with certain conditions could pose a danger to both expectant mother and fetus.
Fever or serious infections during pregnancy must be treated, and acetaminophen is effective with both, the Los Angeles Times quoted a trio of researchers on ADHD. Those researchers wrote that without more details on how acetaminophen causes ADHD, the UCLA findings should be viewed carefully and not derail current practice.
In general, doctors still say take as little as possible of any medication as the healthiest precaution. Noting that high temperatures have been linked to lowered IQ and other problems for babies, UCLA obstetrician and maternal-fetal health specialist Daniel Kahn, uninvolved with the research, told the Los Angeles Times, “It certainly wouldn’t stop me from treating a fever.”