About ABO Group and Rhesus (Rh) Factor
Blood type determines which ABO and Rh antigens are present on the surface of your red blood cells and which corresponding antibodies you carry in plasma — information essential for safe blood transfusions and organ transplants. Rh-negative women of childbearing age require Rh immunoglobulin (RhoGAM) during pregnancy with an Rh-positive partner to prevent haemolytic disease of the newborn. Emerging research also links certain blood types to differential risk for conditions including cardiovascular disease, venous thromboembolism, and COVID-19 severity.