Calcium Accumulation by the Human Fetus

Shaw has characterized the calcium content of the fetus by means of an exponential equation in which the independent variable is gestational age.1,2 However, a plot of his data shows a rather large amount of scatter about the calculated regression line, but no estimate of the magnitude of the deviation from regression is given. The following is another method of dealing with these data, based on the principle of heterogonic, or allometric, growth,3 which states that body calcium content is a power function of body weight.