[Prenatal determination of fetal RHD in maternal plasma: two-years experience of routine clinical use].
OBJECTIVE
To evaluate the predictive value of RHD fetal genotype in maternal plasma of Rh D negative mothers after 10 weeks of gestation in a clinical use.


METHODS
Prospective, comparative study between fetal RHD genotyping in maternal plasma, with amplification of exons 4,5,10 of the RHD gene, by real-time multiplex PCR, and Rh D serology at birth, in 218 pregnancy and their 223 babies, between November 2002 and 2004.


RESULTS
Combining the amplification of three exons, the concordance rate of fetal Rh D genotyping in maternal plasma and baby phenotyping at delivery was 100%. Four women whose the babies were Rh D negative were positive for RHD exon 10 during pregnancy. This positivity was, in three cases, correlated with the presence of RHDpsi pseudogene and in last case, with a haplotype Cdes (r's). RHD genotyping was performed for five twin pregnancies.


CONCLUSIONS
Multiplex PCR using maternal plasma provides perfect prenatal prediction of fetal RHD gene. These results confirm that this non invasive procedure is the preferred method for assessing Rh D fetal status in Rh negative mothers. Using this method for two years in routine practice has led us to modify our management scheme for sensitized Rh D-negative pregnant women.
Minon
J-M
JM
Service de Biologie Clinique, CHR de la Citadelle, boulevard du 12e-de-Ligne-1, 4000 Liège, Belgique.
Schaaps
J-P
JP
Retz
M-C
MC
Dricot
J-F
JF
Foidart
J-M
JM
Senterre
J-M
JM
D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005838:Genotype; D005865:Gestational Age; D006801:Humans; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012203:Rh Isoimmunization / Q000517:prevention & control; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
D012204:Rh-Hr Blood-Group System