Detection of fetal trisomy 18 by short-term culture of maternal peripheral blood

Objective: We report the prenatal detection by fluorescence in situ hybridization analysis of a male fetus with trisomy 18. Study Design: Total nucleated cells recovered from 7 mL of maternal peripheral blood by means of double-density gradient centrifugation were cultured for 3 days in a devised medium. Results: Fetal cells with X- and Y-specific signals were detected in all the established cultures, but the yield and purity were higher in the culture from the 1077 Ficoll layer. Cumulatively, 84 fetal cells were recorded by analysis of 5640 cells. The hematopoietic lineages involved in the production of the fetal cells in culture were not assessed. For the cultures established with the 1119 Ficoll layer, the involvement of progenitors or precursors of the erythroid lineage was assumed because postculture sorting was directed toward cells expressing the erythropoietin receptor. Conclusion: We conclude that culturing total nucleated cells from maternal blood is a new procedure that could prove valuable in the detection of the main fetal aneuploidies affecting pregnant populations. (Am J Obstet Gynecol 2000;183:222-5.)