[Rh (D) alloimmunization and pregnancy. Analysis of the causes after prophylaxis introduction]

Prenatal and postnatal prophylaxis of the Rh (D) haemolytic disease of the newborn have clearly reduced the number of cases but still there are alloimmunizations.

All cases detected in our Hospital in the last 24 years have been reviewed and possible causes analyzed.

From a total of 10,332 deliveries in Rh (D) negative women we have detected 114 anti-D in 86 women. In 74 women anti-D was the only antibody and in 12 there were more antibodies. Data were managed in 3-year periods and we see a progressive decrease in the incidence of alloimmunization with a minimum of 0.03 per 1000 pregnancies in the period 89-91 and a posterior progression to an incidence of 0.12 in the last 3-year period 95-97. The causes were: pregnancies before 1970 in 31, incorrect prophylaxis in 12, despite a correct prophylaxis in 6, previous pregnancies without complete information about the prophylaxis in 13, previous transfusion in 6, previous pregnancies or transfusion in 8 and indetermined in 10.

It is desirable to reduce at minimum the number of Rh (D) alloimmunizations by strictly following the prophylaxis protocols.