Trophoblasts isolated from the maternal circulation: in vitro expansion and potential application in non-invasive prenatal diagnosis.

Prenatal diagnosis based on rare fetal cells in maternal blood is currently not a feasible option. An effort was made to improve cell yields by targeting trophoblast cells. After sorting, the HLA-G-positive cell fraction was analyzed directly or after culture. In situ hybridization technology was applied to prove fetal cell source in samples from women carrying a male fetus and to predict gender in samples without previous knowledge of fetal sex. In vitro culture led to a significant increase in fetal cells and accurate gender prediction in 93% of these samples. This approach might be useful for non-invasive prenatal diagnosis.