Fetal RhD genotyping from maternal plasma

The prenatal diagnosis of fetal rhesus D (RhD) status is useful for the man agement of RhD-negative women with partners heterozygous for the RHD gene. Conventional methods for prenatal fetal RhD status determination involve in vasive procedures such as fetal blood sampling and amniocentesis. The recen t demonstration of the existence of cell-free fetal DNA in maternal plasma and serum opens up the possibility of determining fetal RhD status by analy sis of maternal plasma or serum DNA. This possibility has recently been rea lized by three independent groups of investigators. This development: repre sents an important step towards the routine application of noninvasive feta l blood group diagnosis in sensitized, pregnancies and may become a model f or developing safer noninvasive prenatal tests for other single-gene disord ers.