Analysis of fetal blood cells in the maternal circulation: challenges, ongoing efforts, and potential solutions.

The invasive procedures amniocentesis and chorionic villus sampling (CVS) are routinely applied in pregnancies at risk for fetal abnormalities and the results obtained are the gold standard for prenatal diagnosis. Because these methods of fetal cell procurement involve a 0.5-2% risk for fetal loss, they are recommended mainly in cases at high risk for fetal genetic or cytogenetic abnormalities.