Increased fetal RhD gene in the maternal circulation in early pregnancy is associated with an increased risk of pre-eclampsia.
OBJECTIVE
To determine whether the fetal RhD gene is present in the maternal circulation in early pregnancy prior to the clinical manifestation of pre-eclampsia.


METHODS
This is a nested case-control study.


METHODS
Blood samples were obtained from patients attending for a first antenatal visit.


METHODS
Cases were asymptomatic RhD negative women (n= 23) who subsequently developed pre-eclampsia matched to RhD negative controls (n= 23) for parity and gestational age.


METHODS
Real time PCR using TaqMan primers and probes directed against the RhD gene quantified fetal DNA in the maternal circulation.


METHODS
Quantity of RhD gene detected.


RESULTS
As the copy number of RhD gene per millilitre of whole blood at 15 weeks of gestation increased, there was a significantly increased risk of developing pre-eclampsia. There was a graded association between copy number of RhD gene in early pregnancy and severity of disease with controls having 6942, mild pre-eclamptics 83,273 and severe pre-eclamptics 285,793 copies/mL (logscale 3.6, 4.0 and 4.5, respectively).


CONCLUSIONS
Increased fetal RhD gene is present in the maternal circulation in early pregnancy in women who subsequently develop pre-eclampsia and there appears to be a graded response between the quantity of fetal DNA and severity of pre-eclampsia.
Cotter
Amanda M
AM
Coombe Women's Hospital, Dublin, Ireland.
Martin
Cara M
CM
O'Leary
John J
JJ
Daly
Sean F
SF
D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004247:DNA / Q000032:analysis; D005260:Female; D006801:Humans; D010298:Parity; D016133:Polymerase Chain Reaction / Q000379:methods; D011225:Pre-Eclampsia / Q000097:blood* / Q000175:diagnosis; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods; D018029:Rho(D) Immune Globulin / Q000235:genetics*; D012307:Risk Factors
D015415:Biomarkers; D018029:Rho(D) Immune Globulin; D004247:DNA