During pregnancy the baby is protected by the mothers immune system, and all the nutrients it requires, is given by the mother.

We all know the basic A, B, AB and O blood types, however a single red blood cell is actually much more complex. It contains multiple antigen markers on it.

The Rh blood group is an extra catagorie on top of the A, B, AB, and O blood groups.

The presence of an Rh antigen means you are Rh +, while an absence of it means your are Rh -.

During pregnancy a serious issue can arise, erythroblatosis fetalis/haemolytic disease if the mother is Rh -, while the child is Rh +.

As a Rh+ person you can accept Rh- blood, however if you are Rh- (don’t have the Rh antigen) your body sees the Rh marker as a threat and attacks.

When a mother becomes pregnant with a Rh positive child, some of the babies blood may cross over to the mother.

This will cause the mothers body to produce Rh antibodies.

Although this doesn’t kill the first baby, if the mother becomes pregnant again with a Rh positive child, the immune response will be much faster and attack the babies blood cells.

This required a transfusion of the babies blood after it is born and sometimes in the uterus.