Rhesus factor in some red blood cells in some human beings was named after the rhesus monkey in which it was first discovered. Rhesus factor is an antigen present on the cell membrane of some red blood cells. The people that have it are rhesus positive (Rh ) and those that lack it are rhesus negative (Rh”)
Rhesus factor (Rh): If a person with a Rh negative (a person without Rh antigen) is by mistake given a transfusion of Rh positive blood, his blood cells are stimulated by the presence of the Rh antigen to produce antibodies. The first transfusion does not cause any harm to the patient. But if the same patient is later given a second blood transfusion of Rh-positive, the antibodies already present in the blood of the patient will react with the Rh-antigen of the donated blood and may lead to the death of the patient.
Implications of a marriage between a girl with a negative Rhesus factor and a boy with a positive Rhesus factor.
This marriage may cause complications in childbirth. A Rhesus factor is inheritable. When the girl is Rhesus negative and the boy is Rhesus positive a child resulting from the marriage may inherit the Rhesus positive factor from the father. During pregnancy, labour or miscarriage, if ruptures occur in the placenta, separating the mother=s circulation from that of the foetus, the foetus blood containing positive Rhesus factor seeps into the mother=s blood circulation. The mother=s blood (serum) containing no Rhesus factor forms antibodies. These antibodies seep into the foetal blood circulation and causes the destruction of the red blood cells of the foetus leading to anaemia and jaundice. In most cases the baby may die before birth or immediately after birth. This situation may happen during subsequent pregnancies.
- Blood transfusion: The baby=s entire blood is removed and a negative Rhesus blood is transfused into the baby.
- Immunisation of a negative Rhesus mother with Rhesus antibodies immediately after childbirth. This prevents her blood from forming antibodies which would otherwise destroy the red blood cell of the baby.