Accuracy of prenatal weight estimation using ultrasound in the case of birth weights less than 2000 grams

In this study foetal weight as estimated by ultrasound was compared with the true birth weight of children having a birth weight of less than 2000 g (n = 105). The estimation of foetal weight was achieved using the authors' own diagram containing a curve for the biparietal and the thoracal diameter as well as for the foetal weight. The data for the weight curve were taken from two European populations (Bonn and Winterthur). There was a highly significant correlation between the ultrasonically estimated foetal weight and the true birth weight. Only in the group less than 1200 g a significant overestimation of foetal weight could be shown by using the weight curve of the population of Bonn, whereas the percentage deviation of both weight curves was comparable: when using the curve of Bonn 68% of readings had a deviation of less than 10%, whereas with the curve of Winterthur this was the case for 65% of the readings.