AFP and HbF determination in maternal blood as a parameter of fetomaternal microtransfusion in interventions of the pregnant uterus

: The applicability of AFP assay (radioimmunologic) and of erythrocytes containing Hb-F (Kleihauer et al. 1957) in maternal blood as a means of detecting fetomaternal microtransfusion was examined in 57 cases of abruptio and 65 women in whom genetically indicated amniocentesis was performed. There was a significant increase in AFP postoperatively in 40% of the abruptiones; after amniocenteses such behavior was far less pronounced (18.5%). The count of cells containing Hb-F in maternal blood smears revealed no significant increase in any of the cases examined. A correlation on the basis of these examination results is therefore unlikely. However, an evaluation of them demands that the assay methods used for AFP and Hb-F cells and, above all, their physiology, be taken into account. The diaplacental passage rates of the two substances are probably different, and under certain conditions they may also be produced by the maternal organism to a varying extent. It could be concluded from this that even though the AFP assay involves a simpler method and is more sensitive, neither parameter can replace the other, and therefore neither can be made the basis for a decision against anti-D immunoglobulin prophylaxis.