Trophoblast cells in peripheral blood from pregnant women.

The presence of human trophoblast cells in maternal blood was investigated by the use of flow cytometry and a monoclonal antibody reacting against a specific antigen present on the surface of these cells. Three types of cells derived from the placenta could be detected in the peripheral blood obtained from women between 6 weeks' gestation and term. One group of cells were polynucleated, a second group were diploid, and a third consisted of anucleate cells derived from the syncytiotrophoblast. These cells should be suitable for prenatal diagnosis of chromosomal and biochemical abnormalities.