HAEMOLYTIC DISEASE OF NEWBORN [ HDN ] OCCURS DUE TO Rh ANTIGEN INCOMPATIBILITY. Rh FACTOR IS ANTIGEN D WHICH IS PRESENT ON RBCs OF Rh + VE PERSON WHILE Rh - VE PERSON DO NOT HAVE THIS ANTIGEN.
IF FEMALE [ MOTHER ] IS Rh NEGATIVE AND HER HUSBAND IS Rh POSITIVE, THEN THEIR CHILD CAN BE Rh POSITIVE.
Rh NEGATIVE MOTHER HAS ANTIBODIES AGAINST Rh ANTIGEN. HDN IS NOT A PROBLEM DURING FIRST PREGNANCY IF MOTHERS BLOOD IS NOT PREVIOUSLY EXPOSED TO Rh ANTIGEN. BUT DURING FIRST PREGNANCY MOTHER CAN GET SENSITIZED AGAINST Rh ANTIGEN, IF HER BLOOD COMES IN CONTACT WITH Rh POSITIVE BLOOD OF FOETUS. THIS SENSITIZATION LEADS TO THE FORMATION OF ANTIBODIES [ IgG ] AGAINST Rh ANTIGEN.
IF THE SECOND FOETUS DURING NEXT PREGNANCY, IS ALSO Rh POSITIVE, THEN MOTHERS ANTIBODY FINDS Rh ANTIGEN ON FOETAL RBCs AS FOREIGN. AN IMMUNE RESPONSE IS GENERATED BY IgG ANTIBODIES AGAINST FOETAL Rh ANTIGEN. IgG CROSSES THE PLACENTA AND HAEMOLYSE THE RBCs OF FOETUS. SO, CALLED HAEMOLYTIC DISEASE OF NEWBORN OR ERYTHROBLASTOSIS FOETALIS.
SYMPTOMS: IN MILD TO SEVERE CASES, ANAEMIA OCCURS IN THE FOETUS OR BILIRUBIN [ YELLOW COLOURED PIGMENT ] GETS ACCUMULATED IN AMNIOTIC FLUID. IT CAN BE LETHAL AND CAN CAUSE THE DEATH OF A FOETUS. IN NEWBORNS PALE YELLOW SKIN APPEARS WITH MILD TO SEVERE SYMPTOMS OF ANAEMIA.
TREATMENTS: BLOOD TRANSFUSION CAN BE DONE TO PREVENT ANAEMIA IN THE FOETUS. IN THIS FRESH BLOOD IS TRANSFUSED TO THE FOETUS, REPLACING BILIRUBIN RICH BLOOD [ FORMED FROM HEAMOLYSED RBCs ]. ANTI Rh ANTIBODIES CAN ALSO BE USED TO PREVENT ANTIGEN ANTIBODY REACTION IN FOETUS.
