LOS ANGELES (CBSLA.com) — Women who take acetaminophen while they are pregnant are more likely to have children with behavioral problems, according to a study published in the journal JAMA Pediatrics.

“Acetaminophen use during pregnancy is associated with a higher risk of hyperkinetic disorders and attention-deficit hyperactivity disorder (ADHD)-like behaviors,” wrote the study’s lead author Evie Stergiakouli.

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Acetaminophen is the active ingredient in Tylenol and hundreds of over-the-counter and prescription medicines, including those for allergies, colds, flu and sleeplessness, the Food and Drug Administration said.

More than half the pregnant women in the United States and Europe use acetaminophen, the study said.

Stergiakouli and her colleagues reported 4,415 mothers or 53 percent used acetaminophen at 18 weeks of pregnancy, while 3,381 women or 42 percent took it at 32 weeks.

Women who used acetaminophen at 32 weeks into their pregnancies have higher risks of having kids with emotional and hyperactivity symptoms, according to the findings.

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Of the 7,796 pregnant women studied, 5 percent of their children had behavior problems, researchers said.

Sherry Ross, a gynecologist at Providence Saint John’s Health Center in Santa Monica, said that’s not a large number, but she’s taking notice. “It gives us reason to pause and remind patients that anything you take in pregnancy could potentially be a problem,” he said.

Ross also said there may be other contributing factors. “There are other variables that can come into play that aren’t really monitored well in these types of large studies: Is there a genetic component? Is the mother drinking alcohol or smoking tobacco?” Ross asked.

Researchers admitted more research must be done and said it is important for pregnant women to weigh the risks of not treating their pain.

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This is the fourth study linking it to future behavior problems in kids.