A new report out Monday finds a troubling link: when women take the common painkiller acetaminophen when they are pregnant, their kids may be more likely to have behavioral problems such as hyperactivity. Importantly, just 5% of children displayed any behavioral problems by age 7. This left the authors to hypothesize prenatal brain development may have been influenced by hormones that had been disrupted by the drug. She explained that, as with any medication used by mothers-to-be, it should be used only when necessary. And while just 5 percent of children had behavioral problems at 6 or 7 years old, those who did were more likely to have been born to moms who remembered having used acetaminophen while pregnant, Evie Stergiakouli of the University of Bristol and colleagues reported. Results Maternal prenatal acetaminophen use at 18 (n = 4415; 53%) and 32 weeks of pregnancy (n = 3381; 42%) was associated with higher odds of having conduct problems (risk ratio [RR], 1.42; 95% CI, 1.25-1.62) and hyperactivity symptoms (RR, 1.31; 95% CI, 1.16-1.49), while maternal acetaminophen use at 32 weeks was also associated with higher odds of having emotional symptoms (RR, 1.29; 95% CI, 1.09-1.53) and total difficulties (RR, 1.46; 95% CI, 1.21-1.77). “Children exposed to acetaminophen prenatally are at increased risk of multiple behavioral difficulties.” 
 
 “Children exposed to acetaminophen prenatally are at increased risk of multiple behavioral difficulties, and the associations do not appear to be explained by unmeasured behavioral or social factors linked to acetaminophen use insofar as they are not observed for postnatal or partner’s acetaminophen use," they added. Dr. Hal C. Lawrence, CEO of the American College of Obstetricians and Gynecologists , echoed this concern, noting that the current study did not examine significant details, such as the exact dose taken or the reasons why a mother needed to take medication. Acetaminophen, also known as paracetamol, relieves pain and fever and is the active ingredient in Tylenol and hundreds of over-the-counter and prescription medicines, says the Food and Drug Administration website . "The takeaways here are that physicians should not change clinical practice until definitive prospective research is done and, most importantly, patients should not be frightened away from the many benefits of acetaminophen," said Lawrence. The researchers say that given how common acetaminophen use is, that women should be aware of the findings. Safety questioned 
 
 On its website, the FDA says it has reviewed previous studies exploring prenatal use of acetaminophen and the risk of attention deficit hyperactivity disorder in children. In the United States, an estimated 5.1 million children between the ages of 4 and 17 have ADHD, though nearly 11% of kids -- 6.4 million -- have ever been diagnosed with ADHD, according to the Centers for Disease Control and Prevention.
– A popular medication among pregnant women is linked to higher rates of hyperactivity in children, according to a study published Monday in JAMA Pediatrics. CNN reports acetaminophen is found in Tylenol, as well as cold, flu, and allergy medicines. The study's author, Evie Stergiakouli, says it's "considered safe to use during pregnancy." In fact, acetaminophen is one of the few pain relievers that is considered safe for pregnant women, according to NBC News. That may explain why the study of nearly 7,800 women in the US and Europe found that more than half reported using acetaminophen while pregnant, mostly as a treatment for pain or fever. The study found women who reported using acetaminophen at 18 weeks of pregnancy were more likely to have children with conduct problems and hyperactivity. Women who reported using it at 32 weeks, were more likely to have children with hyperactivity and emotional and conduct problems. Still, only 5% of the children in the study were shown to have any such problems. And medical experts say women shouldn't worry yet and should keep using acetaminophen as directed by their doctors. A spokesperson for the company that makes Tylenol points out the study doesn't show a causal relationship between acetaminophen and hyperactivity.