1. Rh Blood Type The Rhesus Factor
discovered by Karl Landsteiner & Alexander Wiener
Most genetically complex of all blood type systems
Involves 45 different antigens on surface of RBCs
Controlled by genes on Chromosome 1

2. Rh System named after rhesus monkeys used in research to make the antiserum for typing blood samples.

3. If the antiserum agglutinates your blood, you are Rh +, if not, you are Rh-.
Inheritance can be predicted by two alleles: D & d.
D is the dominant trait while d is the recessive trait.
Here is how it may shake out genetically speaking:
DD =homozygous dominant Rh+
Dd =heterozygous dominant Rh+
dd = homozygous recessive Rh-

4. Mother-Fetus Incompatibility
1 out of 1000 are born with this condition.
This occurs when the mother is Rh- (dd) and the father is Rh+ (DD or Dd). Maternal antibodies cross the placenta and destroy fetal red blood cells. The risk increases with each pregnancy. Often the first born will not suffer ill effects because the mother has not developed sufficient antibodies yet. By the next birth, she has and complications begin to arise.

5. Erythroblastosis Fetalis
A transfer of antibodies from the mother’s system takes place across placental boundary into the fetus.
Anti Rh+ antibodies react with fetal blood.
The RBCs of the fetus burst or agglutinate
Newborn babies may have life-threatening anemia due to lack of oxygen in the blood.
Baby is also jaundiced, fevered, & swollen with enlarged liver and spleen.

6. Massive transfusion of Rh+ blood into the baby.
A serum (Rho-GAM) can be given the mother at week 28 of pregnancy that will prevent her blood from developing antibodies against her baby’s blood. It must also be administered 72 hours after birth, as well.