Clinical application of midtrimester non-invasive fetal RHD genotyping and identification of RHD variants in a mixed-ethnic population.

Abstract

OBJECTIVE This study aims to assess the suitability of non-invasive prenatal RHD genotyping in non-immunized midtrimester pregnant women from a mixed ethnic population, to prevent unnecessary anti-D immunoglobulin prophylaxis and to identify RHD variants METHODS Rhesus D-negative pregnant women were offered fetal RHD genotyping at 24 gestational weeks. A total of 284 samples were tested for RHD status using multiplex rt-PCR amplification of exons 5 and 7 of the RHD gene and exons 6 and 10 in selected cases. Women carrying RHD-negative fetuses were counseled about their option to avoid routine antenatal anti-D immunoglobulin administration. Diagnostic accuracy of RHD genotyping was compared with postnatal Rhesus D serotyping. RESULTS A total of 184 positives (65%), 91 negatives (32%) and 7 cases (2.5%) compatibles with RHD variants were detected by RHD genotyping. No false negative results were found, and a single false positive was observed in a twin pregnancy. Genotyping was accepted when offered by 94% of women (284/302), and anti-D immunoglobulin was avoided in 95% (90/95) of RHD-negative fetuses. CONCLUSIONS Non-invasive routine antenatal RHD genotyping at 24 weeks of pregnancy is a highly accurate method, resulting in the avoidance of 95% of unnecessary administrations of anti-D immunoglobulin, with no false negative results.

DOI: 10.1002/pd.4035

Cite this paper

@article{Grande2013ClinicalAO, title={Clinical application of midtrimester non-invasive fetal RHD genotyping and identification of RHD variants in a mixed-ethnic population.}, author={Maribel Grande and Elena Ord{\'o}{\~n}ez and V Cirigliano and Joan Cid and Eva Grau and Anna Pericot and Irene Teixid{\'o} and Jos{\'e} Luis Mar{\'i}n and Antoni Borrell}, journal={Prenatal diagnosis}, year={2013}, volume={33 2}, pages={173-8} }