Mathematical modeling of fetal growth. IV. Evaluation of trunk growth using the abdominal profile area

Growth of the fetal abdomen has been reexamined in a longitudinal study of 32 normally growing fetuses using the abdominal profile area (AA) and the Rossavik growth model. The growth of the fetal abdomen was compared to that of the fetal head. In early pregnancy the growth rate was higher for the fetal head than for the fetal abdomen, whereas the opposite was the case in late pregnancy. The coefficient k was lower, and the s was higher, for AA than for the head profile area (HA), giving a less prominent sigmoid shape to the AA growth curve. The best correlation to fetal weight at birth was found for the AA growth curve as a whole. The AA s-residual correlated best of all single parameters, with the coefficient c of HA being next. The s-residual appears to reflect the nutritional supply available in late pregnancy, and we conclude that fetal weight at birth depends more on this supply than on the genetic factors controlling fetal growth.