[Fetal D gene in maternal plasma should be examined in all immunized Rh(-) pregnant women to avoid invasive procedures].
We have recently developed and published a noninvasive determination of fetal RhD status by examination of cell-free DNA in maternal plasma. The predictive value of the procedure of fetal testing, already published by us, was 99,6%.


OBJECTIVE
To assess the necessity of RhD fetal testing in immunized Rh(-) mothers with Rh(+) partners.


METHODS
Rh(-) mothers with anti-D antibodies, their partners and children.


METHODS
Molecular: RHD gene examination by real-time polymerase chain reaction; analysis of control genes present in the father but not in the mother. Serological: titre of anti-D antibodies, Rh phenotypes.


RESULTS
Among 53 Rh(+) partners of immunized Rh(-) pregnant women, 56,6% were homozygous and 43,6%--heterozygous. The latter ones might have had either Rh(+) or Rh(-) children; in fact, in 52,2% of fetuses the D gene was not detected. Among fetuses of homozygous fathers (based on their phenotypes) 2 fetuses, to our surprise, occured to be Rh(-); however the subsequent genotyping showed that both fathers were heterozygous. The titres of anti-D in both groups of mothers with Rh(-) and Rh(+) fetuses were very similar.


CONCLUSIONS
The examination of fetal D gene by noninvasive method should be performed in each alloimmunised Rh(-) mother if her partner is Rh(+). The prediction of RhD fetal status based on the fathers phenotype can be misleading, thus may result in unnecessary invasive method.
Zupańska
Barbara
B
Instytut Hematologii i Transfuzjologii w Warszawie. zupanska@ihit.waw.pl
Orzińska
Agnieszka
A
Nowaczek-Migas
Maria
M
Guz
Katarzyna
K
Wielgoś
Mirosław
M
Debski
Romuald
R
Gibała
Anna
A
Rumas-Bec
Janina
J
Brojer
Ewa
E
D000328:Adult; D000465:Algorithms; D001788:Blood Grouping and Crossmatching; D005260:Female; D005315:Fetal Diseases / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000628:therapy; D005838:Genotype; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012204:Rh-Hr Blood-Group System / Q000097:blood* / Q000235:genetics*
D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen