Introduction: To determine the amount of blood that predicts postpartum hemorrhage, as defined by standard definition compared to Maryland's Hospital Association's definition.

Methods: This is a retrospective chart review that identified all women in the electronic medical record with PPH (standard definition 500 ml for vaginal delivery [VD] and 1000 ml for cesarean delivery [CD] and Maryland definition [MD] =1000 ml for VD and =1500 ml for CD) as estimated by eBL (n=49) and qBL (n=209)) between September 2014 and September 2015, as estimated by EBL (n=166), and October 2015 and October 2016, as estimated by qBL (n=733). The primary outcome was the area under the receiver-operating-characteristic (ROC) curve (AUC) for blood transfusion in women with PPH. The ROC was generated by calculating the amount of blood loss by each technique and PPH definition, that best predicted blood product transfusion. .

Results: The rate of PPH using the standard definition with eBL and qBL was 5% and 21.23%, respectively (p