Quantitative blood loss after vaginal delivery: a retrospective analysis of 104 079 measurements at 41 institutions.

BACKGROUND: Peripartum quantitative blood loss (QBL) measurement is recommended over visual estimation. However, QBL measurement after vaginal delivery has been inadequately evaluated. The primary aim of this study was to determine the characteristics of QBL measurements from a large, multicenter cohort of patients having vaginal deliveries. We also determined the incidence of postpartum hemorrhage (PPH) and the relationship between gravimetric QBL from weighed sponges vs. volumetric QBL from liquid drape or suction cannister contents. METHODS: Data were collected from 41 institutions in the United States of America that use an automated QBL device after vaginal delivery as part of routine care. The QBL device tracks cumulative blood loss based on gravimetry and volumetric V-drape assessment, automatically subtracting the dry weights of all blood-containing sponges, towels, pads and other supplies as well as the amniotic fluid volume. RESULTS: Between January 2017 and April 2020, 104 079 QBL values were obtained from patients having vaginal deliveries. Total median [IQR] QBL was 171 [61-362] mL. The PPH incidence, stratified by QBL, was 15.2% (>500 mL), 3.4% (>1000 mL), and 1.0% (>1500 mL). The contribution of QBL from V-drapes was 60.6±26.3% of total QBL. CONCLUSION: Results from this large set of QBL measurements and the PPH incidence provide normative "real-world" clinical care values that can be expected as hospitals transition from estimated blood loss to QBL to assess the blood loss at vaginal delivery.