For Physicians. By Physicians.™

ACOG Guidance on Quantification of Blood Loss During OB Hemorrhage


ACOG released new guidance (Nov 2019) on quantification of blood loss during an obstetrical hemorrhage. While there are multiple recommendations, a central theme of the document is that accuracy of quantitative measurement is superior to visual estimation. A multidisciplinary approach is recommended and in addition

Implementation of quantitative assessment of blood loss includes the following two items: 1) use of direct measurement of blood loss (quantitative blood loss) and 2) protocols for collecting and reporting a cumulative record of blood loss postdelivery

How to Quantify Blood Loss (AWHONN Practice Brief)

  • Vaginal Delivery: Use under-buttocks drape
    • Begin quantification following delivery (i.e., prior to placental delivery) | Most fluid prior to delivery include amniotic fluid, urine and feces
    • Record total fluid volume
    • Subtract preplacental fluid from post placental fluid volume | Most fluid following delivery is blood
    • Calculate blood volume from soaked items by subtracting weight of wet item from that of dry (1 g additional weight equals 1 ml blood loss)
    • Cumulative volume: Calculated blood volume from weighted soaked items plus drape volume
  • Cesarean delivery: Use suction device
    • Begin quantification when (1) amniotic sac ruptured or (2) after birth
    • Suction and quantify amniotic fluid prior to placental delivery
    • Quantify blood in suction cannister and drapes after delivery of the placenta
    • Weigh all soaked items as above
    • Cumulative volume: Calculated blood volume from weighted soaked items plus blood in suction canister


  • Visual estimation of blood loss can result in both over and underestimation
  • While quantification of blood loss in an important part of evidence based hemorrhage bundles, clinical utility specific to the quantification approach remains unproven and more research is needed
  • Timeframe for continuing blood loss assessment
    • Evidence is insufficient to recommend a precise time frame for ongoing measurement
    • ACOG suggests “that ongoing blood loss assessment should continue as long as active bleeding is present, or as long as the patient is unstable after a blood loss of more than 1,000 mL, including the postpartum care setting”
  • New Approaches: Artificial intelligence platforms
    • Artificial intelligence-based algorithms that use colorimetric analyses of pictures to quantify blood loss in real-time appear promising
    • ACOG states that while there is some supportive data, “validation of these findings with additional research is needed”

Learn More – Primary Sources:

ACOG Committee Opinion 794: Quantitative Blood Loss in Obstetric Hemorrhage

Postpartum Hemorrhage: ACOG Resource Overview