WASHINGTON, March 3, 2014—In response to a recent study of Tylenol exposure during pregnancy and childhood ADHD, high-risk pregnancy experts are urging caution when interpreting results.
“These results are interesting, but it’s premature to change the advice we give to patients,” said Dr. Vincenzo Berghella, president of the Society for Maternal-Fetal Medicine.
In the recent study of acetaminophen and childhood development, the authors found higher rates of ADHD-like behavioral problems among children whose mothers had taken acetaminophen during pregnancy. In the US, acetaminophen is mostly found in Tylenol as well as other pain medications. More than half of the women included in the study had taken acetaminophen at some point during their pregnancy.
Using a standardized score for ADHD-like behavior, the authors found that 3.4 percent of children whose mothers had taken acetaminophen had an elevated score, compared with 2.5 percent of never-users. This 1.36-fold difference diminished to 1.13-fold when the authors accounted for factors such muscle or joint pain, mental health problems, and fever or illness during pregnancy that differed between mothers who did and did not take acetaminophen.
“The study has a number of limitations and its results need to be considered in context,” Berghella said. “The authors found a less-than-one-percent difference in risk.”
Berghella also noted that an association found in an observational study does not necessarily equate with causation. Unmeasured differences between mothers who did and did not take acetaminophen, such as differences in susceptibility to pain, might be behind the use of acetaminophen as well as explain their child’s risk of ADHD-like behavioral problems. In other words, the reason the acetaminophen was taken could have been the real culprit, and not the acetaminophen itself.
“In fact, as the authors state, maternal infections or immunologic factors have been linked to childhood ADHD. These are the conditions for which acetaminophen is often used, so this is what is called ‘confounding,’ a finding which seems due to a factor, but is in fact due to another issue (e.g. infection) linked to both the exposure (e.g. acetaminophen) and outcome (e.g. ADHD).”
It is also important to note that the association with ADHD was mostly seen with prolonged use, sometimes weeks or months, a practice that is not typical of how acetaminophen is prescribed in most pregnancies. Tylenol is one of the few medications we can use in pregnancy to treat pain and control the temperature during a fever.
“Publicity about the study results might actually lead to worse outcomes for mothers and infants,” Berghella said. “For example, high fever during pregnancy is associated with increased risk of complications. Women with febrile illnesses who don’t treat their fever in order to avoid Tylenol might increase the risk of serious complications.”
Other medications to control pain or fever, such as ibuprofen and other non-steroidal anti-inflammatory drugs, have well-described risks for the fetus, including damage to the developing kidneys and changes in blood flow to the fetal heart. Substituting these pain medications to Tylenol may lead to more harm.
Additional studies are needed in order to determine whether acetaminophen causes ADHD. “We need prospective studies of all drugs used in pregnancy and lactation, not just acetaminophen, so that pregnant women or women considering pregnancy can make informed decisions about treatment,” Berghella said. “These results underscore the need for well-designed studies of medication safety in pregnancy and lactation.”
“Most drug trials do not include pregnant women, leaving mothers and their providers with limited information to weigh the risks and benefits of treatment,” Berghella continued. “This gap in understanding has become increasingly problematic as more women delay childbearing and rates of chronic disease rise, because more mothers than ever before are requiring medications to manage conditions such as diabetes, hypertension, depression, and asthma.”
Women should not take any medications, even over the counter medications, without consulting their care provider. As mentioned above, acetaminophen containing medications are still safer than other medications to control pain or fever. If needed, it should be taken for a limited time. If the symptoms persist after few days on acetaminophen, then follow up with the care provider is needed in order to consider other treatments.
The Society for Maternal-Fetal Medicine (est. 1977) is the premiere membership organization for obstetricians/gynecologists who have additional formal education and training in maternal-fetal medicine. The society is devoted to reducing high-risk pregnancy complications by sharing expertise through continuing education to its 2,000 members on the latest pregnancy assessment and treatment methods. It also serves as an advocate for improving public policy, and expanding research funding and opportunities for maternal-fetal medicine. The group hosts an annual meeting in which groundbreaking new ideas and research in the area of maternal-fetal medicine are shared and discussed. For more information visit www.smfm.org.
Image Credit: Vitaly Valua