Patient selection: pregnant woman at time of term delivery
Parameters:
(1) height in inches
(2) prepregnancy weight in pounds
(3) percent blood volume expansion during pregnancy (default 50%)
estimated blood volume for non-pregnant female of childbearing age =
= 0.5 * (((maternal height in inches) * 50) + ((maternal weight in pounds) * 25))
The expansion of maternal blood volume during pregnancy is 50%, or 1.5 times baseline.
Therefore:
blood volume at delivery =
= 1.5 * 0.5 * (((maternal height in inches) * 50) + ((maternal weight in pounds) * 25)) =
= 0.75 * (((maternal height in inches) * 50) + ((maternal weight in pounds) * 25))
This equation can be converted to meters and kilograms as
(0.75 * 50 * 100/2.54 * (height in meters)) + (0.75 * 25 * 2.2 * (weight in kilograms)) =
= (1476.38 * (height in meters)) + (41.25 * (weight in kg))
