Noninvasive Fetal Rhd Genotyping Using Cell-Free Fetal Dna

Rhesus D (RhD)-negative women who are exposed to RhD-positive red blood cells can develop anti-RhD antibodies, which can cross the placenta and cause fetal anemia. If undiagnosed and untreated, alloimmunization can cause significant perinatal morbidity and mortality. Determining the RhD status of the fetus may guide subsequent management of the pregnancy. Hence, the use of cell-free fetal DNA in maternal blood has been proposed as a noninvasive method to determine fetal RHD genotype.