Detection of syncytiotrophoblast in maternal peripheral and uterine veins using a monoclonal antibody and flow cytometry.

Using a monoclonal antibody (H315) and cytofluorimetry, the presence of deported syncytiotrophoblast was investigated in blood samples collected from peripheral and uterine veins at the time of elective Caesarean sections. In all 10 women studied, a higher incidence of H315-positive syncytiotrophoblast cells was detected in the uterine samples than in peripheral blood, thus confirming that in normal pregnancies a large number of cells are shed from the placenta and gain access into the maternal circulation at the time of delivery.