Question

A woman's first pregnancy is normal but her second pregnancy results in hemolytic disease of the newborn (HDN). The second child needed a transfusion to completely replace the agglutinating blood.
The mother is most likely type __________ and both children are most likely __________.

a) A, Rh-negative; B, Rh-positive
b) A, Rh-positive; B, Rh-negative
c) O, Rh-negative; AB, Rh-negative
d) AB, Rh-positive; O, Rh-negative
e) AB, Rh-positive; O, Rh-positive

Answer 1

Answer:

a) A, Rh-negative; B, Rh-positive

Explanation:

Hemolytic disease of the newborn (HDN) is characterized by rapid breakdown of red blood cells of baby. It usually occurs when the mother has Rh negative blood group and the child has Rh positive blood group. Since mother does not produce Rh antigen her immune system considers Rh antigen as foreign.

During the first pregnancy the blood of mother and child mix due to breakage of placenta or some other reason. Mother's immune system senses the presence of Rh antigen in baby's blood and makes antibodies against it in case it is needed in future. During second pregnancy if the baby again has Rh positive blood group, antibodies against it travel from placenta and fight the Rh positive blood cells. This leads to destruction of baby's blood cells leading to HDN.