A Weight Relationship between the Human Foetus and Placenta

Abstract

The weight relationship between the human fetus and placenta can be expressed by the allometric formula, w = 2.1 w0.67, where w is the placental weight and W the fetal weight. Since the chorionic villous surface area varies as the placental weight, and total fetal metabolism varies approximately as the 2/3 power of fetal weight, it follows from the allometric formula that the extent of the chorionic surface is continuously matched, throughout gestation, to total fetal metabolism.