Rate of Rh immunization after induced abortion

The occurrence of Rh immunization was investigated in 386 secundigravidae whose first pregnancy was terminated by induced abortion and who were not given anti-D immunoglobulin after the induced abortion. Of these, 6 (1.57%) already proved to be seropositive at the beginning of their second pregnancy, another 6 (1.57%) became positive by the end of the second pregnancy, i.e. 3.14% altogether as demonstrated with papain-treated RBC. If instead the indirect antiglobulin (Coombs) test was used, 3 women (0.77%) proved to be positive at the beginning and 9 (2.31%) at the end of the second pregnancy. Supposing that 0.5% of the secundigravidae became immunized during the second pregnancy, the rate of immunization after induced abortion in non-protected cases may be calculated to be 2.64% using the papain technique and 1.81% when the antiglobulin test is applied.