What physiological change is associated with excessive jaundice in newborns?

Excessive jaundice in newborns, also known as neonatal hyperbilirubinemia, is primarily associated with increased bilirubin levels in the bloodstream. Bilirubin is a byproduct of the breakdown of red blood cells, and in newborns, particularly those who are premature, the liver may not be fully mature enough to process and excrete bilirubin efficiently. This accumulation leads to the characteristic yellowing of the skin and eyes seen in jaundice.

Monitoring bilirubin levels is crucial in the management of jaundice, as significantly high levels can cause complications such as kernicterus, a form of brain damage. Therefore, the physiological change marked by excessive jaundice is indeed an increase in bilirubin levels, making that the correct association in this context.