Hemolytic disease of the newborn due to rare alloantibodies.

In the period January 1975 to December 1981, serum samples from 9,525 pregnant women were examined for irregular red cell antibodies. Red cell antibodies were found in 719 cases (7.5%); anti-D antibodies were present in 532 cases (5.5% of the whole series), rare antibodies (other than anti-D) in 187 cases (2%). Seven pregnant women with rare red cell antibodies were followed at our Institute up to delivery. The clinical management, which was based on the diagnostic and therapeutic procedures of hemolytic disease of newborn due to anti-D antibodies, is reported in detail. The findings underline the importance of careful screening for irregular red cell antibodies in all pregnant women, both Rh-negative and Rh-positive, and confirm the validity of Rh clinical management also for moderate or severe immunizations due to rare red cell antibodies.