Jaundice is a common condition in newborn infants, characterized by a yellowing of the baby's skin and eyes caused by the buildup of excess bilirubin in their bloodstream. Bilirubin is released when red blood cells break down in the liver, and if the liver cannot process it adequately, it can accumulate in the blood and cause a yellow appearance. While most cases of infant jaundice are short-lived and will quickly go away with exposure to sunlight, some infants develop jaundice that does not go away very easily. This can be serious and require prompt management and treatment, as untreated jaundice can progress into kernicterus, a rare but serious condition that results in brain damage. Kernicterus can occur when excess levels of bilirubin build up in the brain due to untreated jaundice, and bilirubin can become toxic and cause hyperbilirubinemia, leading to damage to the central nervous system, including the brain. Infants are susceptible to jaundice because their liver doesn't finish developing until up to two years following birth. Infant jaundice is very common and affects up to 60% of newborns. Among infants who are born before 36 weeks of gestation, jaundice affects an average of 80%. Kernicterus can cause damage to the brain and central nervous system and lead to multiple symptoms and complications. Kernicterus can result when an infant's severe jaundice is not properly treated. The primary cause of jaundice is hyperbilirubinemia, which is excess bilirubin that is released into the blood when old red blood cells are broken down. Jaundice in newborns can also be caused by an underlying condition and might appear either earlier or later than physiologic jaundice. There are several risk factors for infant jaundice, including risk factors for severe jaundice that can result in kernicterus, such as preterm birth, bruising during labor and delivery, and incompatible blood types between the mother and infant.