How well do postpartum blood loss and common definitions of postpartum hemorrhage correlate with postpartum anemia and fall in hemoglobin?

Abstract

Postpartum morbidity as measured by hemoglobin markers was common for women with blood loss ≥1000ml and relatively infrequent among women with blood loss 500-999ml. These findings reinforce the importance of severe PPH as the preferred outcome to be used in research. The weak correlation between blood loss and hemoglobin markers also suggests that this relationship is not straightforward and should be carefully interpreted.