At birth, some people lose more blood than average. If you do lose a lot of blood (over 500mL, called a post-partum haemorrhage), then you will likely be offered a blood test from 6 hours after birth to check your haemoglobin levels. If that test shows you have very low levels of haemoglobin (under 80g/L) then you may be offered a blood transfusion.
The other scenario in which you would be offered a blood transfusion is if you are bleeding very heavily and the team feel that it is appropriate to activate a massive haemorrhage pathway. This is an emergency situation and the people caring for you believe that your life will be in danger without a rapid mass blood transfusion (a lot of blood products given very quickly).
Like everything in pregnancy and postpartum, it is your choice whether you accept blood products. If you do not want to accept blood products, please make that clear to the people caring for you. They will still offer blood transfusions if they believe you need them or would benefit from them, but it is important for your care team to know your stance on blood products if you plan to decline them so they can plan any interventions carefully.
If you are offered a standard blood transfusion, the blood bank will need a sample of your blood to ‘cross match’ – to give you blood that your body is most likely to accept without issues. This is not a foolproof system, but transfusion reactions are relatively rare now that this system is used.
Once blood bank has released compatible blood, you will be given the blood via IV line over 2-3 hours. You will have frequent observations of your blood pressure, pulse, temperature, and respiration rate taken to ensure that you are not having a reaction to the blood, and the person administering the blood will stay with you for at least the first 15 minutes of the transfusion. If you feel unwell, itchy, or if you have any pain during the transfusion, please let the person caring for you know immediately.
If your care team activate a massive haemorrhage pathway, you will likely be initially given unmatched ‘universal donor’ blood until the team can get cross-matched blood for you. This scenario is very rare and only happens if you have uncontrolled bleeding, and is activated to save your life in serious circumstances. Even so, it is still your choice whether you accept the intervention.