MacNeil M D, Koong L J
Growth. 1983 Winter;47(4):371-80.
The exponential form of growth was used to describe prenatal growth in mouse, rat, guinea pig, swine, sheep, cattle and man. Instantaneous growth rate was permitted to vary as a function of time and, in litter bearing species, number of fetuses. Models for which instantaneous growth rate decreased linearly in time had a tendency to overestimate fetal weight from mid-gestation until midway through the last trimester of pregnancy and subsequently, underestimate fetal weight. When instantaneous growth rate varied as a quadratic function of time, a more accurate and precise prediction of fetal weights resulted.
指数增长形式被用于描述小鼠、大鼠、豚鼠、猪、绵羊、牛和人类的产前生长。瞬时生长率被允许随时间以及（对于多胎物种）胎儿数量而变化。瞬时生长率随时间呈线性下降的模型往往会高估从妊娠中期到妊娠最后三个月中期的胎儿体重，而在这之后则会低估胎儿体重。当瞬时生长率随时间呈二次函数变化时，对胎儿体重的预测会更准确和精确。
