Blood group antibody screening tests during pregnancy

TLDR

Late‑onset antibodies pose risks of haemolytic disease in newborns and transfusion reactions in mothers. The study aims to define an optimal testing protocol that accounts for antibody production during pregnancy. The protocol seeks to balance maximum clinical safety with minimal resource consumption. Over two years, 667 sera from ~70,000 antenatal patients revealed 726 atypical antibodies, 66% of immunized mothers were rhesus (D) positive, and 30% of antibodies were initially undetected, with 50 of 92 antibody‑producing patients lacking detectable antibodies at 28 weeks. Summary.

Abstract

Summary. In a 2‐year period 667 sera from approximately 70 000 (0·95%) antenatal patients were found to contain 726 atypical red blood cell antibodies. Overall, 66% of the immunized mothers were rhesus (D) positive. Apart from four antibody specificities to rhesus system antigens, knowledge of the rhesus (D) group gave no guide to the ability of the patients to form any of the remaining 21 specificities encountered. Of the 726 antibodies 221 (30%) were not detected in the initial sample tested and 50 of the 92 patients who produced antibodies during pregnancy had not developed detectable antibody when they were sampled at 28 weeks. The significance of these late onset antibodies is discussed both in relation to the risk of haemolytic disease in the newborn and transfusion reactions in the mother. An optimum protocol for testing is defined which takes account of antibody production during the pregnancy and use of this protocol constitutes an attempt to combine maximum clinical safety with minimal consumption of resources.