Ability of an obstetric hemorrhage risk assessment tool to predict quantitative peripartum blood loss

Hemorrhage risk assessment tools have been studied using estimated blood loss. We study the association between peripartum hemorrhage risk assessment score and peripartum quantified blood loss (QBL) in term vaginal and cesarean deliveries.

This is a retrospective analysis conducted on 3,657 patients who underwent term vaginal and cesarean deliveries at a public hospital in New York City. Utilizing the risk assessment tool developed by the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN), patients were categorized into low-, medium-, or high-risk groups for postpartum hemorrhage.

Medium-risk (B=0.08, SE=0.01, p<0.001) and high-risk (B=0.12, SE=0.02, p<0.001) AWHONN scores were associated with significantly higher QBL as compared to low-risk AWHONN score. Medium-risk approached significance (OR: 1.67, 95 % CI: 1.00, 2.79, p=0.050) and high-risk AWHONN score was significantly associated (OR: 1.95, 95 % CI: 1.09, 3.48, p=0.02) with increased odds for postpartum hemorrhage (≥1,000 mL). Each individual factor comprising the AWHONN score whose percentage in our sample was seen in greater than 2.7 % of patients was independently significantly associated with increased QBL (six of nine factors) and postpartum hemorrhage (four of nine factors).

The AWHONN measure previously validated with estimated blood loss predicted obstetric blood loss with QBL. Although not on the basis of the data shown in our study, we believe that QBL should be routinely used to measure obstetric blood loss.