What is the hemolytic disease of the newborn?

Hemolytic disease is the blood disorder that occurs in newborn infants when the Rhesus factor (positive or negative ) in the blood group becomes incompatible between the mother and baby. Rhesus factor incompatibility occurs when an Rh-negative mother carries an Rh-positive fetus, causing hemolytic disease. What is the hemolytic disease of the newborn?