Birth · Emergency
Postpartum Hemorrhage / QBL
ACOG Committee Opinion 794 (2019) and CMQCC quantitative blood loss thresholds for postpartum hemorrhage. Vaginal birth ≥ 500 mL OR cesarean ≥ 1,000 mL OR hemodynamic signs = PPH. Severe and massive thresholds with management framework.
Last reviewed 25 May 2026
QBL — quantitative blood loss / PPH
Postpartum hemorrhage threshold check
Delivery type
mL
Enter measured blood loss to interpret.
Educational tool only — not medical advice. ACOG CO 794 emphasises QUANTITATIVE (gravimetric + volumetric) over visual estimation — visual estimates underestimate blood loss by 30-50 %. Causes of PPH (4 Ts): Tone (uterine atony — most common), Trauma (laceration), Tissue (retained products), Thrombin (coagulopathy). TXA 1g IV within 3 hours of bleeding onset reduces death (WOMAN trial, Lancet 2017).
What does this mean?
Postpartum haemorrhage is the leading cause of maternal death worldwide. The shift to quantitative blood loss (QBL) matters because visual estimation underestimates by 30–50 %; gravimetric weighing of swabs and graduated drapes / suction containers triples accurate recognition. Causes (the 4 Ts): Tone (uterine atony, ~70 % of cases), Trauma (lacerations, ruptured uterus), Tissue (retained placenta, accreta), and Thrombin (coagulopathy / DIC). Bundle: uterine massage + oxytocin (preventive at delivery — AMTSL), then escalate to misoprostol, ergometrine, carboprost, intrauterine balloon, B-Lynch suture, embolisation, hysterectomy. The WOMAN trial (Lancet 2017) showed that tranexamic acid (TXA) 1 g IV within 3 hours of bleeding onset cuts death from PPH by ~30 % — give early, not late. Massive transfusion protocols (PRBC : FFP : PLT 1:1:1) mirror trauma resuscitation.
Introduction
Postpartum hemorrhage (PPH) is bleeding that exceeds physiological thresholds after birth. ACOG Committee Opinion 794 (2019) replaced visual blood loss estimation with quantitative measurement (QBL) — visual EBL underestimates by 30-50 % and delays recognition.
Thresholds (ACOG 2019)
- Vaginal birth ≥ 500 mL = PPH.
- Cesarean birth ≥ 1,000 mL = PPH.
- ANY blood loss + hemodynamic compromise (HR > 110, SBP < 90, oliguria, altered consciousness) = PPH.
- Severe PPH: ≥ 1,000 mL vaginal / ≥ 1,500 mL cesarean.
- Massive PPH: ≥ 2,500 mL or hemodynamic compromise needing transfusion.
The 4 Ts — causes of PPH
- Tone (~80 %) — uterine atony. Massage, uterotonics, balloon tamponade.
- Trauma — lacerations, hematoma, uterine inversion. Repair.
- Tissue — retained products / placenta. Manual removal, evacuation.
- Thrombin — coagulopathy. Transfusion, factor replacement.
Management bundle
- Call for help — senior obstetrician, anaesthetist, midwife coordinator.
- IV access × 2 large-bore cannulae.
- Bloods: FBC, coag, fibrinogen, group & save, +/- crossmatch 4 units.
- IV fluids and uterotonics:
- Oxytocin 5 IU IV slow bolus + 40 IU in 500 mL infusion.
- Ergometrine 0.5 mg IM (contraindicated in hypertension).
- Carboprost (Hemabate) 0.25 mg IM every 15 min (contraindicated in asthma).
- Misoprostol 800-1000 mcg PR/PO.
- Tranexamic acid 1g IV within 3 hours of bleeding onset (WOMAN trial 2017 — reduces death by 31 %).
- Identify cause via 4 Ts assessment.
- Escalate: balloon tamponade (Bakri), B-Lynch suture, uterine artery ligation, hysterectomy.
QBL measurement
- Gravimetric — weigh soaked materials; 1g blood ≈ 1 mL (subtract amniotic fluid).
- Volumetric — calibrated drapes / suction canisters.
- Combined — gold standard.
- Visual EBL underestimates by 30-50 % — abandoned.
Limitations
- QBL requires staff training and equipment; uptake varies.
- Late presentation (secondary PPH up to 12 weeks postpartum) often not captured by QBL on day of delivery.
- Educational only; PPH management is a team event with senior clinical leadership.
Sources
- ACOG. Committee Opinion 794: Quantitative Blood Loss in Obstetric Hemorrhage. 2019.
- CMQCC OB Hemorrhage Toolkit V3.0.
- WOMAN Trial Collaborators. Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN). Lancet 2017;389:2105-2116.
- Begley CM, et al. Active versus expectant management for women in the third stage of labour. Cochrane Database Syst Rev 2019;2:CD007412.
- WHO. Recommendations for the prevention and treatment of postpartum haemorrhage. 2012.
Frequently asked questions
What is QBL?
Quantitative Blood Loss — the actual measured volume of blood lost at delivery, replacing the older 'estimated blood loss' (EBL) approach. Multiple studies show that visual EBL underestimates true blood loss by 30-50 %, leading to delayed PPH recognition. QBL uses gravimetric measurement (weighed soaked drapes and pads, 1g ≈ 1 mL) plus calibrated suction canisters. ACOG CO 794 (2019), CMQCC, AWHONN, and the Joint Commission all endorse QBL as standard of care.
What are the PPH thresholds?
ACOG 2019: ≥ 500 mL after vaginal birth, ≥ 1,000 mL after caesarean. Or ANY blood loss with signs of hypovolemia (HR > 110, SBP < 90, oliguria, altered consciousness) regardless of volume. Severe PPH: ≥ 1,000 mL (vaginal) or ≥ 1,500 mL (cesarean). Massive PPH: ≥ 2,500 mL or hemodynamic compromise. The older 500 mL universal threshold has been replaced because most cesarean births lose 800-1,000 mL routinely without complication.
What are the 4 Ts?
The four causes of PPH: TONE (uterine atony — most common, ~80 %; treat with massage, uterotonics, balloon tamponade), TRAUMA (perineal / vaginal / cervical lacerations, uterine inversion — repair), TISSUE (retained placenta / products of conception — manual removal, evacuation), THROMBIN (coagulopathy — DIC, anticoagulants, von Willebrand, ITP — transfusion, factor replacement). Systematic 4Ts assessment guides management.
What is tranexamic acid (TXA) and when?
Antifibrinolytic that reduces clot breakdown. The WOMAN trial (Lancet 2017, 20,060 women with PPH) showed that 1g IV TXA given within 3 hours of bleeding onset reduced death from bleeding by 31%. Now standard of care; WHO recommends TXA for ALL PPH regardless of cause. The 'within 3 hours' window matters — delayed administration loses most of the benefit.
What's the difference between active and physiological third stage?
Active management: routine prophylactic oxytocin within 1 minute of birth (10 IU IM or 5 IU IV slow bolus), early cord clamping (≥ 60 sec for delayed cord clamping benefits, then clamp), controlled cord traction. Reduces PPH by ~60 % vs physiological management (Begley Cochrane 2019). Standard of care in most settings. Physiological management waits for spontaneous separation; reserved for low-risk women who specifically request it.
How is QBL actually measured?
Gravimetric (weighed materials): weigh dry materials before delivery and again post-delivery soaked in blood — difference in grams ≈ mL of blood (subtracting amniotic fluid). Volumetric (calibrated containers): drape with measurement marks under the perineum; calibrated suction canister. Combined gravimetric + volumetric is most accurate. Commercial under-buttocks drapes with calibration lines simplify the process.
Risk factors for PPH?
Per CMQCC risk score: HIGH — placenta praevia/accreta, ≥ 4 prior CS, Hgb < 8, platelets < 70K. MEDIUM — 1-3 prior CS, fibroids, chorioamnionitis, magnesium sulphate use, BMI ≥ 40, polyhydramnios, multiparity, history of PPH. LOW — singleton, term, no prior CS. Pre-stratification allows hospital teams to prepare (blood products, surgical kit, escalation pathway).