Blood Group & Rhesus
Your blood group describes the markers (antigens) carried on the surface of your red blood cells. The two most important systems are ABO, which gives the groups A, B, AB and O, and Rhesus (Rh), which is either positive or negative. Knowing your group is essential before any transfusion and at the start of every pregnancy.
At YGOPH, every pregnant woman has her blood group checked at the first antenatal visit. If a mother is Rhesus-negative and her baby is Rhesus-positive, her body can make antibodies that harm the baby in a later pregnancy, and this can be prevented. Blood grouping is also done before caesarean sections and other surgery, and our blood bank matches every unit of blood to the patient who receives it.
What does blood grouping involve?
The laboratory mixes your red blood cells with reagents containing antibodies against the A, B and Rhesus D antigens and looks for clumping. It also tests your plasma against known red cells to confirm the ABO result. Before a transfusion, a compatibility test (crossmatch) is carried out between your blood and the donor unit. In pregnancy, a screen for irregular antibodies may also be requested.
- At the first antenatal visit, for every pregnant woman
- Before a caesarean section or any surgery that may need a transfusion
- Severe anaemia or bleeding requiring transfusion
- Newborns of Rhesus-negative mothers, or babies with jaundice in the first day of life
- Blood donation
Good to know
Rhesus-negative mothers
Rhesus-negative blood is less common in Africa than in some other regions, but it does occur. A Rhesus-negative woman whose baby is Rhesus-positive may be exposed to the baby's blood during pregnancy or birth and produce antibodies. An injection of anti-D immunoglobulin, given during pregnancy and within 72 hours after birth, miscarriage or bleeding, prevents this. Your midwife will explain whether you need it.
Blood grouping for newborns
When a mother is Rhesus-negative or has antibodies, or when a baby develops jaundice in the first day of life, the baby's blood group and a direct Coombs test may be checked. These tests help doctors detect haemolytic disease of the newborn, a condition in which the mother's antibodies destroy the baby's red cells.
Safe transfusion
Receiving blood of an incompatible group can cause a serious reaction. That is why the laboratory may check your group on two separate samples and always performs a crossmatch before a transfusion. Keep your blood group card safe and bring it to every hospital visit, but remember that it never replaces the checks carried out before a transfusion.