FETAL CELLS IN MATERNAL BLOOD

Fetal cells have been successfully detected in maternal blood in all t hree trimesters of gestation in a substantial proportion of normal pre gnancies. Various enrichment techniques have been developed for fetal trophoblast cells, leucocytes and nucleated red blood cells. Nucleated red blood cells are considered to be best suited for noninvasive pren atal diagnosis. Fluorescence in-situ hybridization detected the first cases of fetal trisomy in maternal blood after enrichment of fetal nuc leated red blood cells. Despite recent encouraging results, accurate a nd reproducible diagnoses of fetal anomalies by polymerase chain react ion or fluorescence in-situ hybridization require further optimization of enrichment devices and detection protocols.