FRCA Notes

Major Obstetric Haemorrhage

The February 2023 CRQ on obstetric haemorrhage (71.9% pass rate) was well answered.

In March 2026, half the marks for a placenta accreta CRQ related to generic management of MOH; only around 50% of candidates answered correctly on the safe use of cell salvage, tranexamic acid and point-of-care testing, and many lost marks on transfusion triggers specific to the obstetric population.

The curriculum explicitly wants knowledge of "Risk factors, recognition and management of MOH including... use of a massive haemorrhage alert system; the use of blood products and cell salvage; the use of uterotonics and point of care coagulation tests; how the physiological changes of pregnancy affect coagulation and their relevance in this setting; particular causes such as genital tract trauma, uterine atony etc."

Resources

  • Major obstetric haemorrhage occurs in 1 in 270 (3.7/1,000) pregnancies
  • PPH is the leading cause of maternal death worldwide; in the UK haemorrhage was the 8th leading cause of maternal death in 2021 to 2023 (MBRRACE, 2025)
  • Black women died from haemorrhage and amniotic fluid embolism at more than 3 times the rate of white women
  • Delay in recognition, most often due to underestimation of blood loss, is a recurring theme in severe PPH

  • Major obstetric haemorrhage is defined as:
    • Blood loss >1.5L (or >20ml/kg)
    • Drop in haemoglobin concentration by >4g/dL
    • Acute transfusion requirement of >4 units
  • PPH definitions vary between organisations:

Organisation Definition
RCOG Minor 500 to 1000ml; major 1000 to 2000ml; severe >2000ml
WHO (2025) ≥300ml with any abnormal haemodynamic sign, or ≥500ml within 24hrs; severe ≥1000ml
NHS England MCB (2026) Standardised reporting of PPH at ≥1500ml

Classification

  • Ante-partum haemorrhage occurs between 24 weeks and delivery
  • Post-partum haemorrhage occurs after delivery, and can be further classified as:
    • Early (primary) PPH; within 24hrs of delivery
    • Late (secondary) PPH; from 24hrs until 6 weeks post delivery

  • Ante-partum haemorrhage affects 3% of pregnancies

Aetiology

  • 1/3rd due to placental abruption; leads to massive localised consumption of clotting factors and rapidly developing haemostatic incompetence
  • 1/3rd due to placenta praevia ± placenta accreta/increta/percreta
  • 1/3rd due to uterine rupture, or other causes such as ectopic pregnancy

Risk factors


Maternal Utero-placental
Hypertension inc. PET Uterine overdistension
Smoking Placenta praevia
Cocaine or amphetamines Placenta accreta spectrum disorder
Extremes of maternal age Abdominal trauma
Previous abruption
Previous uterine surgery or LSCS


Aetiology

  • The 4 Ts; most cases of PPH have more than one cause:
    • Tone (uterine atony; up to 70% of cases and the leading preventable cause)
    • Trauma e.g. genital tract lacerations, haematoma, uterine inversion or rupture, LSCS (emergency > elective)
    • Tissue e.g. retained products of conception, invasive placenta (particularly causes secondary PPH)
    • Thrombin e.g. congenital or acquired coagulopathy (abruption, AFE, PET/HELLP, IUD, anticoagulants); most frequently hypofibrinogenaemia

Risk factors

  • Most women with severe PPH have no identifiable antenatal risk factor, and around 40% are classed as 'low risk' during pregnancy; every delivery should be treated as a potential PPH

Maternal Utero-placental Labour-associated
Age >40yrs Multiple pregnancy Prolonged labour (>12hrs)
Grand multip (>P4) Polyhydramnios Augmented or induced labour
Obesity Foetal macrosomia (>4kg) Operative vaginal delivery
Previous PPH Fibroid uterus Emergency LSCS
Asian ethnicity Placenta praevia/accreta spectrum disorder Prolonged third stage
Previous LSCS APH or abruption Chorioamnionitis
Coagulopathy or anticoagulation
Antenatal anaemia (Hb <100g/L)

Haematological considerations

  • Anaemia weakens uterine contractility and reduces tolerance of blood loss; a fall in pre-birth Hb of >10g/L increases the risk of PPH by 29%
  • Fibrinogen rises physiologically to 4.5 to 5.5g/L at term, so early PPH is rarely coagulopathic unless due to abruption, AFE or sepsis
  • Fibrinogen is the first clotting factor to fall to critical levels; a fibrinogen <2g/L (or low FIBTEM A5) early in PPH predicts progression to severe haemorrhage

  • Patient Blood Management (PBM) is a multidisciplinary, evidence-based approach to optimising and preserving a patient's own blood
  • It is particularly relevant in obstetrics given the bleeding risks of childbirth and high rates of antenatal anaemia
  • It is built on three pillars:

Pillar Prepartum Peripartum Postpartum
1. Diagnose and treat anaemia and iron deficiency Hb and ferritin each trimester; oral iron; IV iron from 2nd trimester if refractory, intolerant or Hb <80g/L after 34 weeks IV iron ± RBC if Hb <80g/L and bleeding Oral iron if Hb <110g/L; IV iron if Hb <100g/L
2. Minimise blood loss and manage coagulopathy Identify high-risk women; PPH protocols, drills and trolley; plan blood product availability Measured blood loss; uterotonics; TXA; cell salvage; POCT-guided targeted haemostasis Thromboprophylaxis once haemostasis secured
3. Optimise tolerance of anaemia Assess physiological reserve; individualised plan Restrictive but individualised transfusion thresholds Restrictive but individualised transfusion thresholds

  • In practice this means a shift away from fixed ratio, product-focused transfusion protocols towards targeted, concentrate-based replacement guided by repeated laboratory or point-of-care testing
  • Anaesthetists are well placed to deliver PBM through antenatal assessment of high-risk women, early group and save/cross-match, and early communication with the blood bank

Quantitative blood loss

  • Cumulative measured blood loss for all births
  • This combines:
    • Gravimetric measurement: weighing swabs and pads, subtracting dry weight (1g ≈ 1ml)
    • Volumetric measurement: suction, drains and under-buttock drapes, once amniotic fluid has been discounted
  • Running totals should be updated at set intervals (e.g. every 15mins in theatre) and visible to the whole team
  • Measured loss should be interpreted alongside clinical signs: MEWS, shock index and lactate; physiological reserve may mask significant loss until late

Care bundles

  • The WHO first response treatment bundle (uterine massage, oxytocics, TXA, IV fluids, examination and escalation) combined with early detection by calibrated drape reduced severe PPH, laparotomy or death after vaginal birth in the E-MOTIVE trial
  • OBS Cymru (risk assessment, measured blood loss, MDT escalation and POCT-guided fibrinogen replacement) was associated with reduced massive PPH and transfusion across Wales; the UK-wide OBS UK study is ongoing

  • Recite the opening gambit for any clinical emergency:

    • Major obstetric haemorrhage is an anaesthetic & obstetric emergency and I would seek senior anaesthetic support as well as making a rapid but thorough assessment of the patient

  • This will involve making the appropriate 2222 call and activating a major (obstetric) haemorrhage protocol

Resuscitation

  1.  Maintain and, if necessary, secure the airway via endotracheal intubation

  2.  Administer 100% oxygen and ensure adequate ventilation

  3.  Position the patient in either left lateral tilt (ante-partum) or flat/head down (post-partum)
    • Secure 2 x large bore IV access (16G or greater); consider IO access if this proves difficult
    • Take blood for: group & cross-match, FBC, coagulation inc. Clauss fibrinogen, VBG (Hb, lactate, iCa2+), U&E
    • Use a rapid infuser with warming; give O RhD negative or group-specific blood early rather than large volumes of clear fluid
    • Limit crystalloid (up to ~2L) as excess causes dilutional coagulopathy and interstitial oedema
    • Give tranexamic acid early (see Haemostatic Resuscitation)
    • Spin up the cell salvage machine
    • Insert an arterial line and urinary catheter once resources allow

Anaesthetic technique

  • An existing epidural can be topped up for surgery if the patient is haemodynamically stable and there is no coagulopathy
  • General anaesthesia is favoured where there is haemodynamic instability, coagulopathy, or prolonged/extensive surgery (e.g. hysterectomy) is expected
    • RSI with a cardiostable induction agent (e.g. ketamine or reduced dose propofol) and vasopressor support at hand
    • Volatile agents cause dose-dependent uterine relaxation; keep MAC low or consider TIVA when atony is the cause
  • Conversion from neuraxial to GA mid-procedure should not be delayed if the patient deteriorates

Tranexamic acid

  • Universally recommended at PPH onset: 1g IV within 3hrs, repeated once if bleeding continues after 30mins (WOMAN trial)
  • 0.5g is insufficient to inhibit hyperfibrinolysis (TRACES study)
  • There is minimal evidence that prophylactic TXA prevents PPH
  • No excess thrombosis or seizure risk at these doses

Fibrinogen replacement

  • Coagulation testing (Clauss fibrinogen or TEG/ROTEM) is recommended in PPH >1000ml, or with abruption, AFE, IUD, suspected concealed bleeding or maternal cardiac arrest
  • Laboratories should return Clauss fibrinogen results within 1hr
  • Maintain fibrinogen >2g/L (or FIBTEM A5 ≥12mm) with cryoprecipitate or fibrinogen concentrate
  • Pre-emptive fibrinogen given to women with normal levels does not reduce blood loss or transfusion; it should be targeted to measured hypofibrinogenaemia

Point-of-care testing

  • Viscoelastic testing (TEG/ROTEM) gives results in minutes, allowing targeted replacement and the safe withholding of FFP and platelets when haemostasis is adequate
    • Use of VHA was associated with lower total blood loss, but not fewer RBC or plasma transfusions (BJA, 2022)
  • Point-of-care Hb (e.g. HemoCue) should be repeated frequently; PPH deteriorates rapidly and decisions should not be based on a single bedside value
  • NICE does not currently recommend routine POCT on cost-effectiveness grounds; OBS UK includes an economic evaluation

Transfusion triggers

  • Hb may be falsely reassuring (>80g/L) during active haemorrhage; transfuse on the clinical picture and rate of loss
  • Early obstetric haemorrhage is usually not coagulopathic, so fixed ratio FFP is less often needed than in trauma
  • If bleeding continues after 4 units RBC with no coagulation results available, give FFP 15ml/kg
  • Targets for management are:

Factor Target Intervention
Hb Clinical decision when bleeding; >70g/L once bleeding controlled RBC, cell salvage
Fibrinogen >2g/L or FIBTEM A5 ≥12mm Cryoprecipitate, fibrinogen concentrate
PT/APTT <1.5 x normal FFP
Platelets Transfuse if <75 x 109/L to maintain >50 x 109/L Platelet transfusion
Ionised calcium (BJA, 2021) >1.0mmol/L IV calcium chloride/gluconate 10%
Temperature >36°C Active warming, warmed fluids
pH Avoid acidosis Restore perfusion; may necessitate MV

Cell salvage

  • Recommended for anticipated or actual blood loss >1000ml at caesarean delivery, or where transfusion avoidance is important
  • Most cost-effective in high-risk women (e.g. abnormal placentation, severe anaemia)
  • Use separate suction for amniotic fluid where possible and re-infuse through a leucocyte depletion filter
  • RhD negative women with an RhD positive baby require a Kleihauer test and anti-D within 72hrs

Advantages Disadvantages
Reduces allogeneic transfusion Theoretical risk of AFE (not borne out in practice)
No risk of incompatibility or transfusion-transmitted infection Foetal red cell contamination risks alloimmunisation
Immediately available Contains no clotting factors or platelets; dilutional coagulopathy
Often acceptable to Jehovah's Witnesses Hypotension reported with leucocyte depletion filters
Cost-effective in high-risk cases Requires trained staff and set-up time


  • Uterine atony should be managed with uterine massage, bimanual compression and uterotonics:

Drug Dose Cautions
Oxytocin 5IU slow IV (may repeat), then 40IU infusion over 4hrs Hypotension and tachycardia with rapid bolus
Ergometrine 500μg IM or slow IV Hypertension, vomiting, coronary vasospasm; avoid in PET
Carboprost 250μg IM every 15mins up to 8 doses (2mg) Bronchospasm (caution in asthma), hypertension, diarrhoea
Misoprostol 800μg sublingual Pyrexia, shivering, diarrhoea

  • Escalating mechanical and surgical options the anaesthetist should anticipate include:
    • Intra-uterine balloon tamponade e.g. Bakri balloon
    • Uterine compression (B-Lynch) sutures; an early step at caesarean delivery
    • Interventional radiology for uterine artery embolisation (may require transfer)
    • Pelvic vessel ligation
    • Hysterectomy
    • Aortic compression or REBOA as a temporising measure
  • Trauma and retained tissue require examination under anaesthesia, suturing or evacuation

  • HDU or ICU care, with ongoing monitoring of Hb, coagulation and lactate
  • Thromboprophylaxis once haemostasis is secured; indicated after blood loss >1000ml and/or transfusion
  • Treat postpartum anaemia with iron (oral if Hb <110g/L, IV if Hb <100g/L) in preference to transfusion in the non-bleeding patient
  • Kleihauer test and anti-D for RhD negative women where cell salvage was used
  • The trifecta of appropriate documentation, a critical incident form and regular, senior, anaesthetic and obstetric follow-up
  • The Maternal Care Bundle requires an MDT case review within a month for all bleeds >2L and all cases of cryoprecipitate or fibrinogen concentrate use; reviews should include anaesthesia
  • Offer a debrief to the woman and her partner given the risk of long-term psychological morbidity

Haematological

  • Anaemia
  • Coagulopathy in DIC
  • Complications associated with blood transfusion
  • PPH (if already suffered APH)

Non-haematological

  • Infection
  • Shock and multi-organ failure
  • Acute kidney injury (acute tubular necrosis)
  • Sheehan's syndrome (postpartum hypopituitarism)
  • Hysterectomy and reduced fertility
  • Psychological sequelae inc. PTSD
  • Prolonged hospital stay
  • Death