
Blood Transfusion in Obstetrics — A Practical Guide
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)
Restores oxygen-carrying capacity
One unit raises haemoglobin by roughly 1 g/dL
Replaces clotting factors
Used for coagulopathy and in massive transfusion
For thrombocytopenia or platelet dysfunction with bleeding
Target often >50×10⁹/L for delivery/surgery; higher for neuraxial anaesthesia
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
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
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
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
Give Rh-negative blood whenever possible
If Rh-positive blood is unavoidable in an emergency, arrange anti-D afterward
Prioritize iron correction when time allows
Reserve transfusion for severe, symptomatic, or acute-loss cases
Discuss alternatives early — cell salvage, iron, tranexamic acid, meticulous surgical haemostasis
Document wishes clearly; involve institutional ethics support as needed
Recheck hemoglobin before discharge
Continue iron supplementation postpartum
Stop The Transfusion
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
