Rh antibodies were studied during pregnancy at frequent intervals in the blood of 73 mothers of babies with fetal erythroblastosis. The serums containing antibodies were divided in 2 groups : (1) serums with blocking antibodies without saline agglutinins; (2) serums with saline agglutinins and serum-albumin agglutinins, but without blocking antibodies. The correlation of these 2 groups with clinical findings in the newborn showed striking differences: blocking antibodies present in 85 per cent of mothers of babies with hydrops or stillborn, and only in 9 per cent of mothers of babies with icterus gravis.
Predominance of saline agglutinins over serum-albumin favored survival, and vice versa.
In a small group of women with a history of transfusions who gave birth to erythroblastotic babies blocking antibodies were found in 92 per cent.
The number of cases used for this study is admittedly small, and only very guarded conclusions may be drawn. The results, however, are in general agreement with recent studies of Wiener on correlation of antibodies with clinical manifestations, and with results of Levine and others regarding the sensitizing influence of blood transfusions.
Periodic tests for antibodies during pregnancy may permit prognostic conclusions.
An anamnestic Rh antibody reaction is described.