How fever in early pregnancy can cause birth defects

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A fever early during pregnancy is known to cause some heart defects and a cleft lip or palate

Researchers demonstrated it is the fever, and not underlying infection, that causes birth defects

CNN  — 

Running a high fever during early pregnancy is known to be dangerous.

A first-trimester fever can increase a baby’s risk of developing a congenital heart defect and certain facial deformities, such as cleft lip or cleft palate.

But is it the fever or the underlying infection that causes the defect?

A new study published Tuesday in the journal Science Signaling reveals it’s the fever itself that interferes with the development of a baby’s heart and jaw during the first three to eight weeks of pregnancy.

“We need to increase public awareness regarding fevers and birth defects. Women are often hesitant to take medication during pregnancy,” said Dr. Eric Benner, senior author of the study, and a neonatologist and assistant professor of pediatrics at Duke University.

“Doctors should counsel women about the risk of fever and remind them that Tylenol (acetaminophen or paracetomol) is one of the most well-studied drugs in pregnancy and is thought to be safe,” said Benner.

He added that women should ensure they discuss all the risks and benefits of taking medication during pregnancy with their doctors.

Scientific serendipity

Like many scientific discoveries, the new finding is “somewhat accidental,” said study co-author Chunlei Liu, an associate professor in electrical engineering and computer sciences at the University of California, Berkeley.

The discovery came about while he and Benner were developing a way to change the activities of cells by focusing on temperature sensitive ion channel proteins. Ion channels work like mini transportation tunnels in cell walls, allowing the flow of ions (electrical currents) in and out of cells.