title: Improvements to the mathematical description of prenatal growth.
abstract: 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.
mesh_terms: D000818:Animals; D002417:Cattle; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006128:Growth; D006168:Guinea Pigs; D006801:Humans; D051379:Mice; D008954:Models, Biological; D051381:Rats; D012756:Sheep; D013223:Statistics as Topic; D013552:Swine