Weight and Growth Problems Babies in this category include those born prematurely, as well as those born past the normal length of pregnancy. Respiratory Disorders Premature infants often have respiratory difficulties. Some are caused by underdeveloped lungs. Blood Disorders Incompatibility of blood types is a common blood disorder in newborns, as are jaundice and problems with blood sugar and calcium. Heart Disorders Most heart disorders in newborns have no known cause. Some disorders can be managed with medicines, but others require surgery. Fever and Infections Fever and infections in a newborn can be serious. Learn about RSV, thrush, cytomegalovirus, group B streptococcus, and HIV. Other Conditions These conditions include SIDS, blood sugar disorders, hearing loss, and fetal alcohol syndrome.