The provided reference doesn't state how much blood is required for normal delivery, but it does explain the increase in plasma volume during pregnancy. This suggests the question is actually about blood volume changes during pregnancy in preparation for delivery.
The reference indicates a healthy woman with a normal-sized fetus (around 3.3 kg) experiences a plasma volume increase of approximately 1250 ml, which is a little under 50% of the average non-pregnant volume of around 2600 ml for white European women.
Here's a breakdown:
- Non-pregnant plasma volume: ~2600 ml (average for white European women)
- Plasma volume increase during pregnancy: ~1250 ml
- Percentage increase: A little under 50%
This increased plasma volume helps support the growing fetus and prepare the mother's body for the blood loss that occurs during delivery. However, this information doesn't directly answer how much blood is needed for a normal delivery, nor does it reflect the amount of blood loss expected during delivery. This increase reflects the blood volume available and changes in the body during gestation.
