Doctors frequently recommend acetaminophen, commonly found in over-the-counter pain relievers including Tylenol, to pregnant women for treating mild pain. 
 
 But a new study out of Denmark suggests the use of acetaminophen during pregnancy could be associated with ADHD-like behavioral problems in children. 
 
 “(Pregnant women) shouldn’t worry at this point,” says study author Dr. Beate Ritz, professor and chair of the epidemiology department at the University of California, Los Angeles Fielding School of Public Health. “But if I were a woman who was pregnant ... I would try to avoid taking painkillers as much as I can until we know more about this.” 
 
 The study, published Monday in the medical journal JAMA Pediatrics, analyzed data from more than 64,000 children enrolled in the Danish National Birth Cohort study between 1996 and 2002. Mothers in the cohort study reported on their children’s behavior, and the researchers looked at databases to determine how many prescriptions for ADHD drugs were written and how many children received a diagnosis of a severe form of ADHD called hyperkinetic disorder, or HKD. 
 
 The study authors concluded that prenatal exposure to acetaminophen may increase the risk of a child being diagnosed with HKD or being prescribed ADHD medications and “exhibiting ADHD-like behaviors." It's important to note that ADHD-like behaviors are not the same as having ADHD. 
 
 An accompanying editorial published in JAMA Pediatrics emphasizes that the study has found “an interesting observed association,” but that the researchers did not find that acetaminophen causes ADHD. The study authors agree that their results do not show a cause-and-effect relationship. 
 
 The data suggests that taking acetaminophen for longer periods and later in pregnancy is associated with higher risks, Ritz says. When women reported use for 20 weeks or more, their children had a 50% increased risk for receiving ADHD medication, according to the study. 
 
 Ritz says more than half of all mothers in the study reported some acetaminophen use while pregnant. The study measured how many weeks the mother reported taking any amount of acetaminophen but did not take the dosage into account. 
 
 “When used as directed, Tylenol has one of the most favorable safety profiles among over-the-counter pain relievers,” said McNeil Consumer Healthcare, the maker of Tylenol. “We are aware of the recent JAMA Pediatrics study; however, there are no prospective, randomized controlled studies demonstrating a causal link between acetaminophen use during pregnancy and adverse effects on child development." 
 
 The study’s authors suggest that acetaminophen may increase the risk of ADHD by interfering with maternal hormones that are critical for fetal brain development, citing a previous study done using acetaminophen in rats and a study of acetaminophen and autism done with humans. 
 
 “The cited literature is not relevant to the human condition,” says Dr. Max Wiznitzer, pediatric neurologist and associate professor at Case Western Reserve University School of Medicine. “I’m afraid that (women) will think, somehow, that they caused their child’s problem when the study does not tell us that. It tells us that they are linked but does not tell us how.” 
 
 “There are a lot of variables that still need to be considered, such as the fact that ADHD runs in families,” Wiznitzer says. Seventy to 80% of ADHD cases are hereditary, he says. 
 
 The study highlights the importance of not taking a drug’s safety during pregnancy for granted, the accompanying editorial points out. 
 
 “There are nonpharmacological ways to deal with pain,” says Dr. Jeffrey Chapa, head of maternal-fetal medicine at Cleveland Clinic Children’s Hospital. Massages, baths and acupuncture are some alternatives he suggests to help relieve pain. “I think we have to focus a little bit more on that as opposed to just medications.” ||||| 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. 
 
 But doctors have immediately questioned the inevitable headlines, and say this study does not show the pills affect unborn babies. 
 
 And even if it did, the overall rates are low. Just 5 percent of the kids in the study had behavior problems. 
 
 File photo of a pregnant woman. Media for Medical / UIG via Getty Images 
 
 Acetaminophen, sold generically and under the brand name Tylenol, is a top choice for pregnant women to use to control pain and fevers — it’s considered a safe painkiller. 
 
 But a few studies have suggested that it might affect the brain development of unborn children. A study in 2013 found that women who took acetaminophen frequently during pregnancy raised the risk of behavior problems in their children by 70 percent. 
 
 Related: Can Tylenol Cause ADHD? 
 
 British doctors set out to find out more, studying the records of more than 7,700 women who took part in a study when they were pregnant in the early 1990s. 
 
 About half used acetaminophen, also called paracetamol, when they were pregnant. 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. 
 
 “Maternal prenatal acetaminophen use at 18 weeks of pregnancy was associated with higher odds of offspring conduct problems and hyperactivity symptoms while maternal acetaminophen use at 32 weeks of pregnancy was associated with higher odds of offspring having emotional symptoms conduct problems hyperactivity symptoms and total difficulties,” the researchers wrote in the Journal of the American Medical Association’s JAMA Pediatrics. 
 
 “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 Lawrence, CEO of the American College of Obstetricians and Gynecologists, said pregnant women shouldn’t worry. 
 
 “ACOG and ob-gyns across the country have always identified acetaminophen as one of the only safe pain relievers for women during pregnancy,” he said in a statement. 
 
 Related: Studies Find Tylenol/ADHD Link 
 
 “This new study, and other studies that have been conducted in the past, show no clear evidence that proves a direct relationship between the prudent use of acetaminophen during any trimester and developmental issues in children.” 
 
 While acetaminophen is considered a very gentle drug, it is not harmless. Large doses can cause liver damage and even kill. The Food and Drug Administration has asked drug companies to limit how much they put into products. 
 
 The researchers did try to address some of the questions doubters had. They asked the women, for instance, about symptoms that may have caused them to take pain medication. Infections such as influenza can affect brain development — for instance, they are linked to autism. It’s one of the many reasons pregnant women are urged to get flu shots. 
 
 But the surveys didn’t ask one key question, which is how often or at what doses the women took the pills. If the risk of behavior problems went up the more often women took the pills, that would be more of a smoking gun. 
 
 “This is all critical information that is missing in order to begin to ascertain a cause and effect,” Lawrence said. 
 
 “Patients should not be frightened away from the many benefits of acetaminophen. However, as always, any medication taken during pregnancy should be used only as needed, in moderation, and after the expectant mother has consulted with her doctor.” 
 
 “ ACOG and ob-gyns across the country have always identified acetaminophen as one of the only safe pain relievers for women during pregnancy.” 
 
 British experts agreed. 
 
 “It is important to highlight that from these results we cannot determine a direct link between paracetamol usage and any behavioral problem,” said Dr. Tim Overton, spokesman for the Royal College of Obstetricians and Gynaecologists. 
 
 "Women should not be alarmed by the results of this study and we recommend that pregnant women continue to follow current guidance and take the lowest effective dose for the shortest possible time when necessary." 
 
 The researchers say that given how common acetaminophen use is, that women should be aware of the findings. They say there are potential explanations of how pain pills might affect a developing fetus. 
 
 "The mechanism might involve disrupted endocrine function, which is important for neurodevelopment," they wrote. 
 
 Behavioral problems such as attention deficit hyperactivity disorder (ADHD) are being diagnosed more frequently. More than 10 percent of U.S. children, or about 5.8 million kids aged 5 to 17 years old, are now diagnosed with ADHD.
– The bad news about acetaminophen just keeps on coming: A new study finds that use of the drug during pregnancy is linked to "ADHD-like behavioral problems" in children, CNN reports. The Danish study looked at data from more than 64,000 children and found that those who had prenatal exposure to acetaminophen had a 13% higher risk of exhibiting ADHD-like behaviors, a 29% higher risk of being prescribed ADHD medication, and a 37% higher risk of receiving a diagnosis of hyperkinetic disorder, a severe form of ADHD, USA Today reports. The risk increased the later in pregnancy the drug was taken and the longer it was taken. Women who used acetaminophen for 20 weeks or longer had a 50% higher chance of their children being prescribed ADHD medication. But the authors did not find a cause-and-effect relationship, and they note that "exhibiting ADHD-like behaviors" is not the same as actually having ADHD. Right now, doctors consider acetaminophen the "safest" pain reliever for pregnant women, NBC News reports; the study author says pregnant women "shouldn't worry at this point." What could account for the link? The authors think acetaminophen may interfere with key maternal hormones that impact fetal brain development. Another recent study also found that frequent acetaminophen use during pregnancy was linked with a 70% higher risk of behavioral problems in children.