Examination of maternal plasma erythropoietin and activin A concentrations with regard to circulatory erythroblast levels in normal and preeclamptic pregnancies

Abstract

Objectives: Preeclampsia has been shown to be associated with an increased number of fetal and maternal erythroblasts in the maternal circulation, suggesting that preeclampsia involves increased leakage of fetal cells across the placental barrier, as well as increased erythropoiesis. We examined the relationship between circulatory erythroblast levels with maternal plasma concentrations of erythropoietin and activin A.

Methods: In a case-control study, we examined 15 pregnancies affected by preeclampsia and 10 matched controls. Erythroblasts were enriched from maternal blood samples by magnetic cell sorting, enumerated and correlated with corresponding plasma activin A and erythropoietin concentrations.

Results: The proportion of erythroblast was elevated in preeclampsia (0.8 vs. 0.1%, p = 0.023). Erythropoietin and activin A concentrations were significantly elevated in preeclampsia (100.4 vs. 44.5 pg/ml, p = 0.023, and 7.4 vs. 1.85 ng/ml, p = 0.029, respectively). Circulatory erythroblast numbers were found to correlate with plasma activin A concentrations (r = 0.76, p = 0.01) in cases with preeclampsia. No such relationship existed for erythropoietin.

Conclusions: Our data suggest that increased concentrations of activin A promote enhanced levels of erythropoiesis in preeclampsia. As the placenta is one of the major sources of activin A in pregnancy, this increase in activin A-dependent erythropoiesis in preeclampsia may be a reflection of an underlying placental hypoxic condition.