Estimated weight of the term fetus. Accuracy of ultrasound vs. clinical examination.

A prospective analysis was done of the accuracy of fetal weight estimation comparing clinical and ultrasound estimation with actual birth weight in 100 women at term. The mean error of clinical estimation was 277 g, or 79.4 g/kg, for a 7.9% error. The error of ultrasound in the same population was 286 g, or 81.7 g/kg, for an 8.2% error. Analysis of these data revealed no statistical difference between clinical estimation and ultrasound estimation of birth weight in the term fetus, even at the extremes of birth weight.