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Relationship between previous maternal transfusions and haemolytic disease of the foetus and newborn mediated by non-RhD antibodies.

BACKGROUND
The aim of this study was to determine the relationship between non-RhD immunisation and the consequent development of haemolytic disease of the newborn in pregnant women with a history of red blood cell transfusion compared to those without a history of transfusion.


MATERIALS AND METHODS
This retrospective cohort study included all pregnancies with red blood cell antibodies that were tested between 1993 and 2010. Data were obtained from the forms for immunisation tracking at the Department of Transfusion Medicine. Each form contained data on previous maternal transfusions, antibody specificities and whether the antibodies caused haemolytic disease of the newborn.


RESULTS
Clinically significant non-RhD antibodies was found in 214 of 108,000 pregnancies, of which the most frequent were anti-E (n =55), anti-K (n =54), and anti-c (n =52) antibodies. A history of red blood cell transfusion was identified in 102 (48%) of the pregnancies in which non-RhD antibodies were found (in 78% of the anti-K cases, 40% of the anti-c and 18% of the anti-E cases). Non-RhD antibodies caused haemolytic disease of the newborn in 44 cases of which 14 were very severe (2 anti-K, 8 anti-c, 3 anti-Rh17, 1 anti-E). The mother had a positive history of red blood cell transfusion in 39% of the cases of haemolytic disease of the newborn. Anti-c antibodies were involved in all cases with severe haemolytic disease of the newborn and a history of maternal red blood cell transfusion.


CONCLUSION
Primary prevention by using K-negative, Rhc-, RhE-, and RhC-compatible red blood cell transfusion for women younger than 45 years may prevent up to 40% of cases of haemolytic disease of the newborn. Rhc compatibile transfusion is the most important prevention strategy against severe haemolytic disease of the newborn caused by non-RhD antibodies.