How much blood does a pregnant woman have in her system?

6-8 liters: Blood volume increases progressively from 6-8 weeks gestation and reaches a maximum at approximately 32-34 weeks with little change thereafter. The increase in plasma volume (40-50%) is relatively greater than that of red cell mass (20-30%) resulting in hemodilution and a decrease in haemoglobin concentration. Approximately 300-500 cc is lost with vag delivery & up to 1000 cc for c-sections.