How can bilirubin buildup in erythroblastosis fetalis harm a newborn's brain?

In the context of erythroblastosis fetalis, the destruction of fetal red blood cells (hemolysis) leads to the release of large amounts of hemoglobin, which the body breaks down into the bile pigment bilirubin. When bilirubin levels become abnormally high, the pigment can cross into and be deposited within brain tissues.123

This deposition causes a severe form of brain damage known as kernicterus. The accumulation of bilirubin in the brain can result in serious, long-term neurological consequences, including hearing loss, movement disorders such as cerebral palsy, and decreased mental ability. Early symptoms in a newborn may include poor feeding, seizures, decreased movement, and the loss of the startle reflex.321

Fortunately, this damage is often preventable through medical interventions such as phototherapy or exchange transfusions, which help manage or reduce bilirubin levels in the infant's blood.312