1-10. Rh FACTOR

 

Many other flood factors have been isolated. The first one discovered (and the most important one) is the Rhesus (Rh) factor. The name "Rhesus" is taken from the name of the Indian rhesus monkey. This factor was first isolated from experiments with these monkeys. Each person is either Rhesus positive or Rhesus

negative, depending on whether he has or does not have antigens for the Rh factor. Rh-positive people have these antigens while Rh-negative people do not (unless they have been transfused with Rh-positive blood). The amount of transfusion required to produce this reaction varies with the individual. A true "universal donor" would generally be type O and Rh-negative. Serious problems because of the Rh factor can occur during pregnancy if the mother is Rh-negative and he fetus is Rh-positive. Small numbers of the child's red cells escape from the placenta and enter the mother's blood stream. This will cause no problem during the first pregnancy, but she will form antibodies. If she is also carrying a Rh-positive child during the second or subsequent pregnancies, the antibodies from her blood will attack the blood of the fetus and cause anemia in the fetus. Some possibilities are open for countering this problem. The baby can be transfused with Rh-negative blood at birth or anti-Rhesus immune globulin injections can be given to the mother. The stage of the pregnancy when the situation is discovered will usually determine which procedure should be used.