Prevention and diagnostics of haemolytic disease of the fetus and newborn

Haemolytic disease of the newborn (HDN), also known as haemolytic disease of the fetus and newborn (HDFN), develops in the fetus when erythrocyte alloantibodies produced by the mother pass through the placenta. Severe form of HDFN is mainly caused by anti-D antibodies, but it can also be caused by many other types of antibodies, most often by anti-Kell (anti-K), anti-c, anti-E in anti-C. In order to prevent sensitisation to erythrocyte antigens, every pregnant woman is tested for blood group AB0, D, K and for irregular antibodies (IAT–indirect antiglobulin test). For D-negative women IAT is repeated in the 28th week of pregnancy, followed by an injection of anti-D immnunoglobulin (Ig anti-D) when indicated. At the Blood Transfusion Centre of Slovenia, we have recently started to determine the fetal D status from a maternal blood sample in order to avoid the unnecessary application of Ig anti-D to women bearing Dnegative fetuses.