A study published in the journal JAMA Pediatrics found that use of Tylenol (acetaminophen) during pregnancy was associated with a higher risk of behavioral problems such as attention-deficit/hyperactivity disorder (ADHD). The study was led by Evie Stergiakouli, a lecturer in genetic epidemiology at the University of Bristol, who said that in pregnant women who took Tylenol, there were higher rates of behavioral problems appearing in children by age seven.
Researchers found that taking acetaminophen between 18 and 32 weeks in pregnancy was linked to a 42 percent elevated risk of behavioral problems and a 31 percent increased risk of hyperactivity. Among women who took Tylenol at 32 weeks of pregnancy, the study pointed to a 29 percent increased risk of emotional problems and a 46 percent increased risk of overall behavioral issues.
The study did not find any similar relationships among mothers who used Tylenol after giving birth or among fathers who used Tylenol. “Only acetaminophen use during pregnancy has the potential to cause behavioral problems in the offspring,” said Stergiakouli, according to HealthDay.
The findings indicate a correlational relationship, but does not prove cause-and-effect. Stergiakouli says pregnant women should still take Tylenol if they need it. The over-the-counter painkiller is generally considered safe during pregnancy. Stergiakouli said that failure to treat a fever during pregnancy could, for instance, lead to premature labor. The American Academy of Family Physicians estimates that two-thirds of women use Tylenol while pregnant.
The study surveyed 8,000 mothers who enrolled between 1991 and 1992. Researchers asked about the woman’s acetaminophen use at 18 and 32 weeks during pregnancy. Participants were questioned again when their children were 5 years old. Mothers then completed a follow-up questionnaire inquiring about their children’s behavioral problems at age 7. Roughly 53 percent of participants said they used acetaminophen at 18 weeks of pregnancy and 42 percent reported using the drug at 32 weeks. Behavioral problems were reported in 5 percent of children.
According to the National Health Service, an estimated 2 to 5 percent of British children and 11 percent of American children have ADHD.
The authors hypothesized that, if there is a mechanism responsible for this association, it may involve Tylenol changing the level of the mother’s hormones or directly crossing the placenta.
Dr. Noel Strong, an assistant professor of obstetrics, gynecology and reproductive science with the Icahn School of Medicine at Mount Sinai in New York City, points out that ADHD is a complex disorder that may be affected by many different factors. ADHD is most likely not caused by a single facet. “There are many degrees of separation and many bridges of evidence that would have to be crossed before you can establish a causal relationship,” said Strong, according to HealthDay. “This needs a lot more science behind it.”
The study findings echo two other large-scale studies suggesting that Tylenol exposure during pregnancy is associated with negative health consequences on a baby’s brain, according to Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Cohen Children’s Medical Center in New Hyde Park, N.Y. He noted that using Tylenol during pregnancy does not automatically lead to ADHD.