PREDICTION OF BIRTH-WEIGHT USING THE ROSSAVIK GROWTH-MODEL - A STUDY IN A DUTCH POPULATION

Objectives: To evaluate the Rossavik growth model for predicting birth weight in a Dutch population and to evaluate growth cessation near te rm. Study Design: Birth weight was predicted at various ages between 3 8 and 42 weeks, menstrual age (MA), and at birth age in 50 normal infa nts using two sets of ultrasound measurements obtained before 28 weeks , MA. Predicted birth weights were compared to actual weights. The mea n percentage difference was used as a measure of systematic error and the standard deviation as a measure of random error. Linear regression analysis was used to evaluate the relationship between percentage dif ferences and birth age. To evaluate the individual growth potential, t he Growth Potential Realization Index for weight (GPRI(WT)) was determ ined for each fetus. Results: The predictions at 39 and 39.15 weeks, M A, were accurate without systematic error and with a random error of /-9.3%. Prediction at 38 weeks showed a statistical underestimation (m ean +/- SD = -5.8% +/- 8.8), and statistical overestimations were foun d for predictions after 39.15 weeks and at birth age. A relationship b etween percentage differences and birth age was not found for predicti ons between 39.15 and 40 weeks, MA. These findings indicate that growt h cessation occurred at 39.15 weeks, MA. Using birth weights predicted at 39.15 weeks, MA, GPRI(WT) were calculated. The mean GPRI(WT) value was not significantly different from 100% (p > 0.05), and individual GPRI(WT) values ranged from 84% to 114%. Conclusions: The Rossavik gro wth model can be used to predict birth weight in a Dutch population. H owever, growth cessation near term appears to occur later than previou sly reported in other populations. (C) 1997 John Wiley & Sons, Inc.