Rh disease, also known as hemolytic disease of the newborn (HDN), is a condition that occurs when a mother's Rh factor (a protein found on red blood cells) is incompatible with her baby's Rh factor. This can cause red blood cells in the baby to break down, leading to anemia, jaundice, and other complications. Synonyms for Rh disease include erythroblastosis fetalis, isoimmunization, Rh incompatibility, and Rh sensitization. Treatment may include prenatal care, medications such as Rhogam, blood transfusions, or early delivery via C-section. Prevention involves identifying and treating Rh incompatibility during pregnancy. Without appropriate intervention, Rh disease can be life-threatening for newborns.