RhIG Administration Research Articles

Ultrasound determination of fetal sex

The technique of specific mixed agglutination to detect small populations of Rh-positive blood cells was described in detail by Greendyke and associates. This technique has been modified by Sebring and Polesky3 and applied to the detection of fetomaternal hemorrhage. The specific mixed-agglutination technique can theoretically detect a fetomaternal bleed of as little as 0.02 ml of Rh-positive fetal blood in the circulation of a 60 kg Rh-negative woman.• 3 In the case reported here, the negative specific mixed-agglutination test indicated that the supposed fetal cells in the maternal circulation were Rh negative. These hemoglobin F -containing cells may have been either fetal or maternal in origin; in neither case was Rh-IG administration indicated. We recommend the use of the specific mixedagglutination technique to determine the fetal Rh blood group in Rh-negative women who appear to have experienced fetomaternal bleeding. In the future it it likely that maternal blood samples will be evaluated more frequently for the presence of fetomaternal hemorrhage. The specific mixed-agglutination technique may be used to guide the management of Rhnegative pregnant women who appear to have fetal blood in the circulation.