Postpartum hemorrhage risk assessment—revisiting the three-tiered classification of low- medium- and high-risk

Abstract

ACOG promulgates classification of individuals admitted for delivery into three-tiers for postpartum hemorrhage (PPH): Low-, Medium-, or High-Risk. We sought to report the frequency of each tier and the clinical outcomes linked to each one. Over 12 consecutive months, charts of all singletons who delivered at a Level IV maternal center were reviewed. Multiple gestations and those transferred after delivery were excluded. Using pre-defined criteria, chart abstraction was done by qualified medical personnel, and data quality was audited on 10% of the charts by staff not involved in data abstraction. Using the California Maternal Quality Care Collaborative (CMQCC) schema, with the known risk factors until delivery, all singletons were categorized into three tiers. PPH was defined as estimated or quantitative blood loss ≥1,000 mL. We contrasted risks of composite maternal morbidity (CMM) among all classification groups, with a relative risk (RR) with a 95% confidence interval (CI) as the effect measure calculated using Poisson regression adjusted for potential confounders. Of the 4,516 singletons, 1,854 (41%) were categorized as being low-risk, 1,239 (27%) were medium-, and 1423 (32%) as high-risk. The risk factors for the 3 groups are in Table 1. The risk of CMM was 19% higher in the medium versus low-risk groups (RR 1.19, 95% CI 1.03-1.36) and 16% higher comparing high versus low-risk groups (RR 1.16, 95% CI 1.02-1.32), but not amongst the medium vs. high-risk groups (aRR 0.98, 95% CI 0.85-1.12). Blood loss of at least 1,000 mL and transfusion followed a similar pattern to the CMM (Table 2). The three maternal deaths were not directly related to PPH. At our Level IV maternal center, the three-tiered postpartum hemorrhage classification performed poorly since over 1 out 5 “low-risk” had hemorrhagic sequelae and no difference in outcomes was noted between medium versus high-risk groups. A better predictive model is needed for PPH and associated morbidity.View Large Image Figure ViewerDownload Hi-res image Download (PPT)