詳細ガイド 近日公開
Postpartum Haemorrhage Risk Scoreの包括的な教育ガイドを準備中です。ステップバイステップの解説、数式、実例、専門家のヒントをお届けしますので、もうしばらくお待ちください。
Postpartum Haemorrhage (PPH) risk scoring is a structured antenatal and intrapartum assessment tool that identifies women at increased risk of abnormal blood loss after delivery. PPH is defined as blood loss exceeding 500 mL after vaginal birth or 1000 mL after caesarean section within 24 hours; severe PPH is defined as blood loss over 1500 mL or any blood loss causing haemodynamic instability. PPH is the leading cause of maternal mortality worldwide, accounting for approximately 27% of maternal deaths globally, and remains a significant cause of maternal morbidity in high-income countries. The California Maternal Quality Care Collaborative (CMQCC) PPH Risk Assessment Tool stratifies risk at hospital admission into low, medium, and high risk based on antepartum and intrapartum factors. High-risk factors include placenta praevia, placenta accreta spectrum, previous uterine surgery (CS or myomectomy), and active bleeding on admission. Medium-risk factors include grand multiparity (4+ prior births), twin or higher-order multiple pregnancy, prior uterine surgery, obesity (BMI >40), haematocrit below 30%, known bleeding disorder, large uterine fibroids, and magnesium sulphate therapy. Uterotonic agents (oxytocin, ergometrine, misoprostol, carboprost, tranexamic acid) are the cornerstone of PPH prevention and treatment, with active management of the third stage of labour (AMTSL) — comprising prophylactic uterotonics, controlled cord traction, and uterine massage — reducing PPH incidence by approximately 60%.
PPH Risk Score = Sum of risk factor weights (CMQCC toolkit); Low risk = 0 medium/high factors; Medium risk = 1+ medium factors; High risk = any single high-risk factor present
- 1Assess and document all antepartum risk factors at booking and 36 weeks: placenta position (praevia/accreta), previous CS or uterine surgery, grand multiparity, multiple pregnancy, known coagulopathy, anaemia, pre-eclampsia.
- 2Reassess risk on admission to the labour ward, adding intrapartum factors: prolonged labour (>12 hours active phase), chorioamnionitis, magnesium sulphate use, general anaesthesia.
- 3Classify risk level: Low (no medium or high factors), Medium (1+ medium factors), High (any single high-risk factor including placenta praevia, suspected accreta, prior PPH >1500 mL, active haemorrhage).
- 4For HIGH-risk patients: ensure senior obstetric and anaesthetic presence; cross-match blood; insert large-bore IV access; plan delivery in an operating theatre-equipped setting; prepare uterotonic agents; alert haematology and blood bank.
- 5Administer active management of the third stage of labour (AMTSL) for all births: 10 IU oxytocin IM (or 5 IU IV slowly) immediately after delivery of the baby.
- 6If PPH occurs: call for help immediately; apply the HAEMOSTASIS mnemonic (H-Ask for help; A-Assess and resuscitate; E-Establish aetiology; M-Massage uterus; O-Oxytocin and other uterotonics; S-Shift to theatre if needed; T-Tamponade; A-Apply compression sutures; S-Systemic pelvic devascularisation; I-Interventional radiology; S-Subtotal/total hysterectomy).
- 7Administer tranexamic acid (TXA) 1 g IV within 3 hours of PPH onset (and repeat 1 g if bleeding continues after 30 minutes or restarts) — supported by the WOMAN trial evidence.
Ensure oxytocin drawn up ready at delivery
No medium or high-risk factors present. Standard active management with 10 IU oxytocin IM at delivery of the anterior shoulder or immediately after birth is appropriate.
Correct pre-existing anaemia before delivery; have ergometrine available
Grand multiparity (5+ births) and mild anaemia place this woman in the medium-risk category. IV oxytocin infusion rather than IM bolus alone is reasonable. Iron supplementation should have been given during pregnancy.
Cross-match 4 units packed red cells and 2 FFP; consult vascular surgery for potential hysterectomy
Placenta praevia combined with prior CS creates a high probability of placenta accreta spectrum disorder. PPH risk is extreme. Pre-operative embolisation of uterine arteries may be considered; cell salvage during delivery is standard in many specialist centres.
WOMAN trial: TXA within 3 hours reduces PPH mortality by 31%
PPH exceeding 500 mL with ongoing bleeding after first-line uterotonics qualifies for TXA. The 1 g dose is fixed (not weight-based). Time from PPH onset is critical — benefit diminishes rapidly after 3 hours.
Antenatal risk stratification to assign women to appropriate care pathways and delivery settings., representing an important application area for the Pph Risk Score in professional and analytical contexts where accurate pph risk score calculations directly support informed decision-making, strategic planning, and performance optimization
Labour ward admission assessments to ensure high-risk women have appropriate IV access and senior cover., representing an important application area for the Pph Risk Score in professional and analytical contexts where accurate pph risk score calculations directly support informed decision-making, strategic planning, and performance optimization
Triggering massive transfusion protocols in major obstetric haemorrhage., representing an important application area for the Pph Risk Score in professional and analytical contexts where accurate pph risk score calculations directly support informed decision-making, strategic planning, and performance optimization
Audit of time-to-TXA administration as a quality indicator in maternity units., representing an important application area for the Pph Risk Score in professional and analytical contexts where accurate pph risk score calculations directly support informed decision-making, strategic planning, and performance optimization
Training simulations for obstetric haemorrhage drills in midwifery and obstetric teams., representing an important application area for the Pph Risk Score in professional and analytical contexts where accurate pph risk score calculations directly support informed decision-making, strategic planning, and performance optimization
Coagulation disorders
In the Pph Risk Score, this scenario requires additional caution when interpreting pph risk score results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when pph risk score calculations fall into non-standard territory.
In the Pph Risk Score, this scenario requires additional caution when interpreting pph risk score results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when pph risk score calculations fall into non-standard territory.
Home birth or midwifery unit
{'title': 'Home birth or midwifery unit', 'body': 'Women planning birth outside consultant-led units should be assessed for PPH risk. High-risk women should be advised to deliver in a consultant-led unit. All midwives attending home births must carry oxytocin and be trained in PPH recognition and initial management, with rapid transfer protocols in place.'}
Anaemia pre-delivery
In the Pph Risk Score, this scenario requires additional caution when interpreting pph risk score results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when pph risk score calculations fall into non-standard territory.
| Risk Level | Factors | Action |
|---|---|---|
| Low | No medium or high-risk factors | AMTSL; standard monitoring |
| Medium | Grand multiparity, twin pregnancy, prior CS, obesity, Hb <10, fibroids, pre-eclampsia | IV access x2, group and save, senior midwife |
| High | Placenta praevia, suspected accreta, prior PPH >1500 mL, bleeding on admission, platelets <50 | Cross-match 4 units, senior obstetrician, theatres on standby, inform haematology |
What is the definition of PPH?
PPH is defined as blood loss of 500 mL or more within 24 hours of vaginal birth, or 1000 mL or more within 24 hours of caesarean section. Severe PPH is defined as blood loss exceeding 1000–1500 mL after vaginal birth (thresholds vary by guideline) or any blood loss causing clinical signs of haemodynamic compromise. Many clinicians use a functional definition: any blood loss that causes a 10% fall in haematocrit or requires blood transfusion.
What is active management of the third stage of labour?
AMTSL consists of three components: (1) prophylactic uterotonic administration (typically 10 IU oxytocin IM or IV) immediately after delivery of the baby; (2) controlled cord traction to deliver the placenta; and (3) uterine massage after delivery of the placenta. AMTSL reduces the risk of PPH by approximately 60% compared to expectant management and is recommended by WHO and NICE for all births.
What uterotonics are used for PPH treatment?
Step-up uterotonic protocol: (1) Oxytocin 10 IU IM or slow IV bolus; (2) Ergometrine 0.5 mg IM/IV (contraindicated in hypertension); (3) Syntocinon infusion (40 IU in 500 mL over 4 hours); (4) Carboprost (Hemabate) 0.25 mg IM every 15 minutes up to 8 doses (contraindicated in asthma); (5) Misoprostol 800 mcg sublingually (when injectables not available); (6) Tranexamic acid 1 g IV (fibrinolysis inhibitor, not a uterotonic but essential in PPH).
What is the WOMAN trial?
The WOMAN (World Maternal Antifibrinolytic) trial (Lancet 2017) was a large randomised controlled trial in 21,000+ women across 193 hospitals in 21 countries. It demonstrated that tranexamic acid (1 g IV) given within 3 hours of PPH reduced death due to bleeding by 31% (from 1.9% to 1.5%), without increasing thrombotic complications. WOMAN trial evidence underpins universal TXA recommendations in PPH guidelines.
What is placenta accreta spectrum?
Placenta accreta spectrum (PAS) disorder includes accreta (villous tissue attached to myometrium without intervening decidua), increta (invasion into myometrium), and percreta (invasion through myometrium into serosa or adjacent organs). It is primarily caused by previous uterine surgery (CS, myomectomy) and is associated with placenta praevia. PAS carries extremely high PPH risk — estimated average blood loss at delivery is 3–5 litres. Management requires specialist multidisciplinary planning.
How accurate is clinical estimation of blood loss?
Clinical estimation of blood loss at delivery is notoriously inaccurate. Studies consistently show that visual estimation underestimates true blood loss by 30–50%, particularly in rapid or large-volume haemorrhages. Quantitative blood loss (QBL) assessment using calibrated drapes, weighing blood-soaked materials, and suction canister measurement is now recommended in many high-income settings to trigger earlier intervention.
When is uterine balloon tamponade used?
Uterine balloon tamponade (e.g., Bakri balloon, SOS Tamponade Catheter) is used for atonic PPH that does not respond to uterotonics and bimanual compression. The balloon is inserted into the uterine cavity and inflated with saline (typically 300–500 mL) to create tamponade pressure exceeding arterial pressure and stop bleeding. It is a temporising measure bridging to surgical intervention or interventional radiology.
What is the role of cell salvage in PPH?
Intraoperative cell salvage (autologous blood recycling) collects, washes, and reinfuses the patient's own blood lost during surgery. It is recommended by NICE and RCOG for caesarean deliveries in high PPH-risk women (PAS, placenta praevia, refusal of allogenic blood products). Concerns about reinfusing foetal cells or amniotic fluid are managed by the use of leukocyte-depletion filters.
プロのヒント
Use the shock index (heart rate / systolic BP) to rapidly assess haemodynamic status during PPH. A shock index >1.0 indicates significant haemodynamic compromise and should trigger immediate escalation. Normal shock index is 0.5–0.7; >1.7 indicates severe shock requiring resuscitation.
ご存知でしたか？
The WOMAN trial enrolled over 21,000 women in 193 hospitals across 21 countries and showed that simply giving an inexpensive drug — tranexamic acid, costing approximately $1–2 per dose — within 3 hours of PPH could prevent 1 in 3 deaths from bleeding. If universally applied, TXA could prevent an estimated 20,000–40,000 maternal deaths per year globally.