BackgroundThe routine prenatal determination of fetal RhD blood group would be very useful in the management of pregnancies in RhD-negative women, as up to 40% of these pregnancies bear a RhD-negative fetus. The fetal DNA present in maternal plasma offers an opportunity for risk-free prenatal diagnosis.AimThis study focused on the feasibility and accuracy of large-scale RhD fetal diagnosis in non-immunized and anti-D immunized RhD-negative women.MethodsPlasma DNA was extracted from 893 RhD-negative pregnant women and amplified in exons 7 and 10 of theRHDgene using conventional and real-time PCR. The results were then compared with theRHDfetal genotype determined on amniotic cells and/or the RhD phenotype of the red blood cells of the infants at birth.ResultsAfter exclusion of 42 samples from women exhibiting a nonfunctional or rearrangedRHDgene, fetal RhD status was predicted with a 99.5% accuracy. A strategy is also proposed to avoid the small number of false-positive and -negative results.ConclusionFetalRHDgenotyping from maternal plasma DNA in different clinical situations may be used with confidence.