Prediction of normal fetal growth by the Rossavik growth model using two scans before 27 weeks, menstrual age.

Individual growth curve standards for five fetal anatomic parameters (head and abdominal circumferences, head and abdominal cubes, and femur diaphysis length) and estimated fetal weight were prospectively developed in 70 pregnant women who delivered infants with growth considered appropriate-for-menstrual age. For this purpose, we used the Rossavik growth model (P = c(t) kappa + s(t], model specification functions previously reported, and the data of two scans before 27.0 weeks of menstrual age, separated by an interval of at least 5 weeks. The anatomic parameters and estimated weights of these fetuses in the last 14 weeks of gestation were found to have values close to their projected standards. Whereas there was a significant, although small, systematic error of overprediction for most of the parameters and estimated fetal weight, deviations between observed and expected values were, with few exceptions, within the ranges established by Deter for normal growth. This study demonstrates that the Rossavik growth model could be used to predict normal fetal growth in a sample of patients different from those from which the model was developed.