Maternal and fetal erythropoietin: physiological aspects and clinical significance.

Erythropoietin (EPO) is of special interest in the perinatal period in the mother and fetus. On the one hand, thanks to the recent development of highly sensitive radio-immunoassays and the ability to monitor endogenous EPO production, we can now study the physiological aspects of maternal and fetal erythropoiesis and materno-fetal interrelations, and diagnose raised EPO levels as markers of oxygen deficiency. On the other hand, the availability of recombinant human EPO (rHuEPO) permits therapeutic intervention against anaemia during and after pregnancy. This paper reviews available studies showing a rise in maternal and fetal EPO levels in parallel with gestational age and, in certain pathological states of pregnancy, grossly raised EPO levels in amniotic fluid and fetal blood entirely unrelated to maternal values. The theoretical and experimental arguments against transplacental passage of EPO in the human are discussed. Initial results with rHuEPO have shown rapid correction of maternal post-partum anaemia. No studies on its use during pregnancy are available to date.