Tag: immunity and blood groups

Rh incompatibility usually isn't a problem if it's the mother's first pregnancy because, unless there's some sort of abnormality, the fetus's blood does not normally enter the mother's circulatory system during the course of the pregnancy. However, during second child, the mother's and baby's blood can intermingle. If this happens, the mother's body recognizes the Rh protein as a foreign substance and might begin making antibodies (protein molecules in the immune system that recognize, and later work to destroy foreign substances) against the Rh proteins. Rh antibodies are harmless until the mother's second or later pregnancies. If she is ever carrying another Rh-positive child, her Rh antibodies will recognize the Rh proteins on the surface of the baby's blood cells as foreign, and pass into the baby's bloodstream and attack those cells. This can lead to swelling and rupture of the baby's RBCs. A baby's blood count can get dangerously low when this condition, known as a haemolytic or Rh disease of the newborn, happens.

If a woman who is Rh- negative married to a man who is Rh- positive produces a baby may have Rh- positive blood, inherited from the father. Rh antibodies are harmless until the mother's second or later pregnancies. If she is ever carrying another Rh- positive child, her Rh antibodies will recognize the Rh proteins on the surface of the baby's blood cells as foreign and attack those cells. This can lead to rupture of the baby's RBCs known as haemolytic or Rh disease of the newborn or erythroblastosis foetalis. 

When a woman is pregnant having Rh negative blood group and the blood group of the foetus is Rh positive, then her baby's blood type will be incompatible with her own. This can cause a condition known as erythroblastosis fetalis, where the mother's red blood cells attack those of the baby as there would any foreign invaders. Rh incompatibility and ABO incompatibility are the two main cause. Both are associated with blood type. Thus, the correct answer is option C.

Rh incompatibility arises when mother and the baby carries different protein factors. The problem arises when mother is Rh negative and the child she is carrying is Rh positive. This can take place even when two blood groups with different proteins are either mixed in a test tube or transfused into a person. Rh negative people do not have this protein and if Rh positive blood is mixed with Rh negative blood anti Rh antibodies develop which can lead to problems. 

Erythroblastosis fetalis also called the hemolytic disease of the newborn, type of anemia in which the red blood cells (erythrocytes) of a fetus are destroyed in a maternal immune reaction resulting from a blood group incompatibility between the fetus and its mother. Symptoms of erythroblastosis fetalis range from mild to severe; death of the fetus or newborn sometimes results.

The Rh system is responsible for the most severe form of the disease, which can occur when a Rh-negative woman (a woman whose blood cells lack the Rh factor) conceives a Rh-positive fetus. Sensitization of the mother’s immune system (immunization) occurs when fetal red blood cells that carry the Rh factor (an antigen in this context) cross the placental barrier and enter the mother’s bloodstream. They stimulate the production of antibodies, some of which pass across the placenta into fetal circulation and lyse, or break apart, the red blood cells of the fetus (hemolysis). Hence option B is correct.