ANTIBODY TITER AFTER ADMINISTRATION OF ANTEPARTUM RH IMMUNE PROPHYLAXIS - NORMALITY OR SENSITIZATION

Antibody screening tests were performed in 29 unsensitized pregnant wo men after antepartum Rh immune prophylaxis, using the indirect Coombs test (ICT) and a more sensitive ID-microtyping-system (IDM). With the ICT, anti-D antibodies were detected in 85% for at least 4 weeks and a t most 8 weeks after immunisation. The maximum titer was 1:8. With the IDM, 97% showed antibodies against 'D' for at least 4 weeks and at mo st 11 weeks with a maximum of 1:16. The IDM titer was always 1 to 3 st eps more sensitive than the ICT. After postpartum Rh immune prophylaxi s, anti-D titers were again positive in many of the patients (ICT: 42% ; IDM: 60%). In conclusion, it is nearly always possible to measure an tibodies against 'D' after antepartum Rh immune prophylaxis and IDM wa s superior in comparison to ICT. However, maternal isoimmunisation to the rhesus antigen cannot be excluded for sure and patients have then to be controlled. As isoimmunisation could not be confirmed in any of our patients, postpartum Rh immune prophylaxis has to be administered even after detection of an antibody titer against 'D' after antepartum Rh prophylaxis.