New York, Oct 12 (IANS) Babies whose mothers' suffered from fever in the first trimester of pregnancy may be at risk of developing some heart defects and facial deformities such as cleft lip or palate, a study has shown. The findings showed that fever itself interferes with the development of the heart and jaw during the first three to eight weeks of pregnancy, causing deformities within the embryo. "Congenital heart and cranial facial defects are very common in live births, but most of the time they have unknown causes," said Chunlei Liu, associate professor at University of California - Berkeley. "Our study identified a specific molecular pathway that links maternal fever directly to some of those defects," Liu added. A portion of congenital birth defects or deformities could be prevented if fevers are treated through the judicious use of acetaminophen during the first trimester, the researchers suggested. If women are planning to become pregnant, the doctors should not only advise them to take prenatal vitamins and folic acid, but also inform them that 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, the researchers explained. For the study, published in the journal Science Signalling, the researchers observed zebra fish and chicken embryos to see how fever impacts a developing foetus. They found that neural crest cells -- cells that are critical building blocks for the heart, face and jaw -- contain temperature-sensitive properties. When those neural crest cells created transient fever conditions, the embryos developed craniofacial irregularities and heart defects, including double outlet right ventricle, Tetralogy of Fallot and other outflow obstructions. Importantly, the type of defect depends on whether the fever occurs during heart development or head and face development, the researchers noted.