ABSTRACT
During normal pregnancy there is a decrease in the hematocrit due to a disproportionate
increase in the blood volume compared with the red cell mass. Using a new enzyme-linked
immunoassay (Amgen Diagnostics), serum erythropoietin was quantified in normal nonanemic
pregnancies throughout gestation and in third trimester anemic patients. We found
that the mean hematocrit in normal pregnancy reached a nadir late in the second trimester
and the serum erythropoietin plateaued at a 50% increase. Those pregnancies complicated
by anemia defined by a hematocrit less than 30 vol% demonstrated a statistically significant
increase in serum erythropoietin above those not anemic.
