Nicolaides et al estimated the fetoplacental blood volume from 18 to 32 weeks of gestation. This can help determine the transfusion requirements in infants with erythroblastosis.
adjusted blood volume in mL =
= (blood volume in mL) * (mean normal fetal hemoglobin) / 15
where:
• 15 is the mean normal hemoglobin at 40 weeks gestation.
Week Gestation
Adjusted Blood Volume
18
20 mL
20
25 mL
22
37 mL
24
52 mL
26
70 mL
28
95 mL
30
125 mL
32
163 mL
This data was analyzed in JMP and an approximating equation is:
