Tylenol may no longer be the “safe” drug for pregnant women.
According to new research published in JAMA Pediatrics, pregnant women who took acetaminophen, also known as paracetamol and the main ingredient in Tylenol, had children with a higher risk for hyperactivity and behavioral problems.
The connection was one of association and not causation: researchers do not know whether taking acetaminophen caused the hyperactivity, and conduct problems in kids; just that women who took it in the second and third trimesters of their pregnancies had more kids with these disorders.
Acetaminophen has long been considered the safe thing moms could take, for everything from fevers to the many muscle aches and pains that come from adding 25 to 50 pounds of weight to your body. This leaves pregnant women with yet another risk factor to weigh, along with alcohol, coffee and other pain relievers, among other things.
The researchers studied 7,796 mothers enrolled in the British Avon Longitudinal Study of Parents (ALSPAC) between 1991 and 1992, also studying their children and partners.
Fifty-three percent of the mothers reported using acetaminophen at 18 weeks of pregnancy, and 42% reported using it at 32 weeks. After pregnancy, 89% of mothers and 84% of partners used it.
Mothers who tool the medication at 18 weeks of pregnancy were associated with a greater chance of her child becoming hyperactive or developing conduct problems. At 32 weeks into pregnancy, a mother’s use of acetaminophen was linked to higher chance of her child having emotional issues, conduct problems and hyperactivity symptoms. There was no association between mothers who took the medication after the child was born and a higher incidence of behavior issues.
Symptoms of ADHD tend to be recognizable around age five. In the UK, about 4% of kids aged 5-15 have been diagnosed. The study showed that 5% of children displayed any behavioral problems by age 7.
The researchers tried to isolate other potential prenatal causes of the hyperactivity and attention problems, including smoking, alcohol use, socioeconomics and genetics. Accounting for these possibilities, they still found acetaminophen use to have an association with higher levels of ADHD.
The study was not the first to find an association. One study from the Danish National Birth Cohort found a similar risk, as did one looking at mother-child pairs in New Zealand. A separate study looked at sibling pairs and acetaminophen use during pregnancy and found adverse developmental outcomes at age 3 years.
And yet the lead author, and the head of the American College of Obstetricians and Gynecologists, said pregnant moms were ok to take the medication when needed.
“Patients should not be frightened away from the many benefits of acetaminophen,” said Hal C. Lawrence, head of the American College of Obstetricians and Gynecologists, in a statement, adding that physicians should not change clinical practice until more research was is done.
He emphasized the lack of causation, noting that: “The brain does not stop developing until at least 15 months of age, which leaves room for children to be exposed to a number of factors that could potentially lead to behavioral issues.”
Evie Stergiakouli, lead author of the research, told CNN, “Acetaminophen is considered safe to use during pregnancy,” explaining to them that, as with any medication used by pregnant mothers, it should be used only when necessary.
The study had limitations. The researchers did not asked detailed questions on dose or duration, and the questionnaires about behavioral issues were taken buy mothers and not medical professionals.