Many women in their early pregnancies are hesitant to take medications for fear that they may endanger their baby. However, it may be prudent to treat fevers in early pregnancy, as researchers have now officially linked fevers to birth defects.
"We have known since the early 1980s that fevers are associated with birth defects, but how that was happening has been a complete mystery," said Dr. Eric Benner, a neonatologist and assistant professor of pediatrics at Duke University, and the study’s senior author. Specifically, doctors didn’t know whether the high temperatures (fever) or the underlying infection was responsible for the birth defects.
The answer to this question came about serendipitously, as Benner and his team were studying ways to change the activities of cells with temperature. But they soon realized that a specific type of cells, called neural crest cells, were extremely sensitive to temperatures.
"We found that these neural crest cells contain temperature-sensitive ion channels that typically are found in your sensory neurons," Dr. Benner said. "They're the channels that, when you stick your hand in a hot cup of water, tell your body the temperature has changed."
Neural crest cells are also vital in the development of facial features, such as the jaw and face, as well as the heart. The team hypothesized that fevers interfere with two temperature-sensitive ion channels in the neural crest cells (TRPV1 and TRPV4), which results in the birth defects. Indeed, experiments in zebrafish and chicken embryos confirm their suspicions. Furthermore, they showed that fevers occurring during head and face development corresponded to facial deformities, such as cleft lip or palate. Likewise, fevers occurring during heart development corresponded to heart defects.
"We need to increase public awareness regarding fevers and birth defects. Women are often hesitant to take medication during pregnancy," said Dr. Benner. "While doctors advise most women to avoid any drug during pregnancy, there may be benefits to taking acetaminophen to reduce fever. Women should discuss all risks and benefits with their doctors."
"My hope is that right now, as women are planning to become pregnant and their doctors advise them to start taking prenatal vitamins and folic acid, their doctor also informs them if they get a fever, they should not hesitate to call and consider taking a fever reducer, specifically acetaminophen (Tylenol), which has been studied extensively and determined to be safe during the first trimester,” he said. "These findings suggest we can reduce the risk of birth defects that otherwise could lead to serious health complications requiring surgery.”
"I hope moving forward, we can educate more women about fever as a risk factor for birth defects and let them know they shouldn't just tough it out if they develop a fever," Dr. Benner said. "They should ask their doctor before getting pregnant whether they may benefit from taking a fever-reducer such as acetaminophen in the event they develop a fever."
Additional sources: Duke University