### Description

The blood volume of a woman at the time of delivery for a term pregnancy can be estimated from the pre-pregnancy blood volume and the pregnancy-associated volume expansion (hypervolemia of pregnancy).

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))