Blood Transfusion in Obstetrics — A Practical Guide
Transfusion is often life-saving in obstetric haemorrhage and severe anaemia — but every component carries real
risks, so it should be targeted to a clinical need, not given reflexively to correct a number. This guide
covers components, compatibility testing, massive transfusion, and how to recognize a reaction early. For the
haemorrhage side of this picture, see our companion Hemorrhagic Shock in Obstetrics guide.
ЁЯй╕ AT A GLANCE — WHEN TO TRANSFUSE
Acute haemorrhage with instability: transfuse based on clinical status and ongoing loss — not a single lab value
Severe symptomatic anaemia (e.g., Hb <7 g/dL, or <8 g/dL with symptoms or cardiac disease) not responding to other measures
Planned transfusion for a known bleeding disorder or anticipated major blood loss (e.g., placenta accreta spectrum surgery)
GREEN: normal or mild anaemia, no active bleeding — oral iron and monitoring
AMBER: moderate anaemia or minor ongoing bleeding — consider transfusion based on symptoms and trend
RED: major haemorrhage or haemodynamic instability — transfuse urgently, activate massive transfusion protocol if criteria are met
Packed Red Cells (PRBC)
Restores oxygen-carrying capacity
One unit raises haemoglobin by roughly 1 g/dL
Fresh Frozen Plasma (FFP)
Replaces clotting factors
Used for coagulopathy and in massive transfusion
Platelets
For thrombocytopenia or platelet dysfunction with bleeding
Target often >50×10⁹/L for delivery/surgery; higher for neuraxial anaesthesia
Cryoprecipitate
Concentrated fibrinogen and factor VIII/XIII
Used when fibrinogen is low — remember pregnancy's normal fibrinogen runs higher, so "low-normal" may already be too low
ЁЯзп MASSIVE TRANSFUSION PROTOCOL (MTP)
Typical Activation Criteria
Anticipated need for >4 units PRBC within 1 hour, or replacing >50% of blood volume within 3 hours
Ongoing severe haemorrhage with haemodynamic instability, regardless of exact unit count
Core Principles
Transfuse in a balanced ratio — PRBC : FFP : platelets, roughly 1:1:1 — rather than red cells alone
Correct fibrinogen with cryoprecipitate if it falls below the pregnancy-adjusted target
Give tranexamic acid early — benefit is time-dependent (see our Hemorrhagic Shock guide for the 3-hour window)
Limit plain crystalloid — over-resuscitating with fluid dilutes clotting factors and worsens coagulopathy
ЁЯзк CROSS-MATCHING & COMPATIBILITY
Type & screen: identifies blood group and checks for antibodies — fast, doesn't reserve specific units
Type & crossmatch: full compatibility testing against reserved units — more thorough, but typically takes 30–45 minutes
Emergency uncrossmatched O-negative blood: used when there's no time to wait; switch to crossmatched blood as soon as it's available
Rh-negative woman given Rh-positive blood in an emergency: notify the blood bank and give an appropriate dose of anti-D afterward — this is a bigger dose than routine prophylaxis and should be calculated with transfusion medicine input.
ЁЯЪи RECOGNIZE A TRANSFUSION REACTION
Fever, chills, back pain, or dark urine → possible acute haemolytic reaction
Hives, itching, or wheeze → allergic reaction, possible anaphylaxis
Sudden breathlessness or hypoxia within 6 hours → possible TRALI (transfusion-related acute lung injury)
Breathlessness, hypertension, signs of fluid overload → possible TACO (transfusion-associated circulatory overload)
⚠️ WATCH FOR DURING MASSIVE TRANSFUSION
1
Hypothermia — actively warm all fluids and blood products
2
Hypocalcaemia — from citrate in stored blood; check and correct calcium
3
Hyperkalaemia — from stored red cells, especially with rapid large-volume transfusion
4
Dilutional coagulopathy — if PRBC is given without matching FFP/platelets
Rh-Negative Women
Give Rh-negative blood whenever possible
If Rh-positive blood is unavoidable in an emergency, arrange anti-D afterward
Antenatal Anaemia
Prioritize iron correction when time allows
Reserve transfusion for severe, symptomatic, or acute-loss cases
Declining Blood Products
Discuss alternatives early — cell salvage, iron, tranexamic acid, meticulous surgical haemostasis
Document wishes clearly; involve institutional ethics support as needed
After Major Transfusion
Recheck hemoglobin before discharge
Continue iron supplementation postpartum
First Response
Stop The Transfusion
Whatever the suspected reaction, this is always the first move. Stopping immediately limits how much incompatible or reactive blood the patient receives — it gives every other intervention room to work.
Stop the transfusion and disconnect the blood bag, keeping the IV line open with plain saline
Recheck patient identity and unit labels immediately — a mismatch is the single most common cause of acute haemolytic reactions
Notify the blood bank right away; send the remaining unit and a fresh patient blood sample for workup
Treat symptomatically while investigating — oxygen, fluids, antihistamines or steroids for allergic reactions, escalate urgently for anaphylaxis or instability
Reminder: most severe reactions are preventable with correct patient and unit identification — not exotic testing.