haemolytic disease of the newborn

a serious disease affecting FOETUSES and newborn babies, which is characterized by HAEMOLYSIS , leading to ANAEMIA and severe JAUNDICE . In severe cases the foetus may die because of heart failure and OEDEMA (termed hydrops foetalis). The usual cause is incompatibility between the BLOOD of the mother and that of the foetus. Generally the foetus has Rh-positive red blood cells (i.e. they contain the rhesus factor, see BLOOD GROUPS ) while that of the mother is Rh negative. The mother produces ANTIBODIES to the Rh factor present in the foetal blood, and these are passed to the foetus in the placental circulation. This then produces the haemolysis of the foetal red blood cells ( ERYTHROCYTES ). The incidence of the disease has been greatly reduced by giving a Rh-negative mother an injection of anti-D IMMUNOGLOBULIN , following the birth of a Rh-positive baby. This prevents the formation of the antibodies that would harm a subsequent baby and is also given to Rh-negative women following miscarriages or abortions.