Increased fetal erythroblasts in women who subsequently develop pre-eclampsia

In pregnancies complicated by pre-eclampsia (PET) and/ or intrauterine grow th restriction (IUGR) there is an increased number of fetal cells in the ma ternal circulation. The aim of this study was to investigate whether this i ncrease in fetal cells precedes the onset of these pregnancy complications. Doppler ultrasound studies at 24 weeks gestation have shown that increased impedance to flow in the uterine arteries identifies pregnancies with impa ired placental perfusion that subsequently develop PET and/or IUGR, We obta ined maternal blood from 18 pregnancies with abnormal Doppler results at 22 -24 weeks gestation and from 10 normal controls, Fetal erythroblasts were e nriched from maternal blood by triple density gradient centrifugation and m agnetic cell sorting with CD71 antibody, and the percentage of these erythr oblasts was determined, The median proportion of fetal erythroblasts in the group with abnormal Doppler results was 4.5% (range 1-12%), which was sign ificantly higher than in the control group [median 1% (range 0-3%; P < 0.00 1)]. Furthermore, within the group with abnormal Doppler the median proport ion of fetal erythroblasts was higher in the 10 cases which subsequently de veloped PET and/or IUGR [median 5.5% (range 3-12%)], than in those with nor mal pregnancy outcome [median 2% (range 1-5%; P < 0.01)]. These findings su ggest that impaired placental perfusion is associated with an increase in f ete-maternal cell traffic, which precedes the onset of PET and/or IUGR by s everal weeks.