A simple method to estimate volume for fetal intravascular transfusions.

We derived a constant termed the transfusion coefficient to simplify the estimation of the fetal intravascular transfusion volume. The product of the estimated fetal weight (g) and 0.02 (transfusion coefficient), estimates the transfusion volume (ml) required to increase the fetal hematocrit by approximately 10 percentage points. Our estimation was comparable to Mandelbrot's technique and better than Plecas' method for estimating fetal transfusion volumes. Utilizing the transfusion coefficient to estimate the intravascular transfusion volume for an anemic fetus is simple, rapid and accurate.