STUDY DESIGN AND METHODS: In each of the five Danish health care regions, blood samples were drawn from D− women in Gestational Week 25. DNA was extracted from the maternal plasma and analyzed for the presence of the RHD gene by real‐time polymerase chain reaction targeting two RHD exons. Prediction of the fetal RhD type was compared with serologic typing of the newborn in 2312 pregnancies, which represented the first 6 months of routine analysis.
RESULTS: For the detection of fetal RHD , the sensitivity was 99.9%. The accuracy was 96.5%. The recommendation for unnecessary antenatal RhD prophylaxis for women carrying a D− fetus was correctly avoided in 862 cases (37.3%), while 39 women (1.7%) were recommended for antenatal RhD prophylaxis unnecessarily. Two RHD + fetuses (0.087%) were not detected, and antenatal RhIG was not given.
CONCLUSION: These data represent the first demonstration of the reliability of routine antenatal fetal RHD screening in D−, pregnant women to ascertain the requirement for antenatal RhD prophylaxis. Our findings should encourage the implementation of such screening programs worldwide, to reduce the unnecessary use of RhIG.