Human fetal weight and placental weight growth curves. A mathematical analysis from a population at sea level.

A mathematical analysis of human fetal and placental growth curves was made on data collected prospectively from a population at sea level. Both the fetal and placental growth curves can best be described by a form of the logistic equation inhibited growth model. The fetal growth rate reaches its maximum approximately 4 weeks after the placental growth rate has reached its maximum. Growth rate constants were calculated for several populations at various altitudes.