Researchers have known for decades that fevers in the first trimester of pregnancy increase the risk for some heart defects and facial deformities such as cleft lip or palate in developing fetus. Researchers now have evidence indicating that fever is responsible for interferes with the development of the heart and jaw during the first three to eight weeks of pregnancy.
The results suggest a portion of congenital birth defects could be prevented by lowering the mother’s fever with the use of acetaminophen during the first trimester. Women who are planning to become pregnant are advise to start taking prenatal vitamins and folic acid, they should take drug that can reduce the effects of fever if they have fever during the first trimester
Acetaminophen (Tylenol), which has been studied extensively and determined to be safe during the first trimester is recommended. The use of nonsteroidal anti-inflammatory drugs NSAIDs such as ibuprofen and aspirin also reduce fevers, but some NSAIDs are not safe to use during the later stages of pregnancy.
To observe how fever impacts a developing fetus, the researchers studied zebra embryo. Among their discoveries, they found that neural crest cells, the cells that are critical building blocks for the heart, face and jaw – contain temperature-sensitive properties. These neural crest cells contain temperature-sensitive ion channels that typically are found in the sensory neurons. They’re the channels that, when you stick your hand in a hot cup of water, tell your body the temperature has changed.
The researchers engineered a noninvasive magnet-based technology to create fever-like conditions in two specific temperature-sensitive ion channels called TRPV1 and TRPV4 in the neural crest cells involved in developing the heart and face. When those neural crest cells were subjected to conditions mimicking a transient fever, the embryos developed craniofacial irregularities and heart defects, including double outlet right ventricle, Tetralogy of Fallot and other outflow obstructions. The type of defect depends on whether the fever occurs during heart development or head and face development.