The effect of Rh-D immunoprophylaxis with hyperimmune anti-D-immunoglobulin on the occurrence of RhD immunization in pregnancy]

During prenatal immunohaematological examination in the period from January 1, 1991 to December 31, 1995, in the Croatian Institute of Transfusion Medicine we tested sera of 5107 RhD negative women. All of them had pregnancies in their medical history. The frequency of Rh immunization was 4.6% in 1991; 4.1% in 1992; 2.5% in 1993; 2.5% in 1994 and 2.4% in 1995. Rh immunization during the first pregnancy was observed in 0.46% of women, in 1.8% during the second, in 9.4% during the third, in 22.4% during the fourth pregnancy, and 33.8% in women with more than five pregnancies. In women that have no abortions in their medical history, anti-D alloantibodies were found with the frequency of 0.46% at the end of the first pregnancy, 1.2% at the end of the second pregnancy, 5.9% at the end of the third pregnancy, 14.3% at the end of the fourth pregnancy, and 15.3% in women with more than five pregnancies. The frequency of anti-D alloantibodies in women who in their medical history have only abortions is 3.4% after the first abortion, 10.5% after the second, 17.8% after the third and 20.8% after the fourth or more abortions. The frequency of antibodies of anti-D specificities in women who had abortions and births is 17.1% at the end of the third pregnancy, 26.2% at the end of the fourth pregnancy, and 42.7% after more than five pregnancies. The frequency of anti-D alloantibodies in women who were protected from Rh immunization by hyperimmune anti-D globulin is 1%. The obtained results demonstrate that prevention of Rh immunization by hyperimmune anti-D globulin does not comprise all the Rh negative women, and is especially inadequate after abortions and multiple pregnancies.