(a) To assess the validity of ultrasound estimation of fetal weight and to compare the accuracy of 17 sonographic formulae to predict fetal birth weight. (b) To propose a new formula that improves predictions in our population.
We performed a prospective study that included 282 pregnant women at term. Seventeen formulae were used to predict fetal weight. To assess the accuracy of the predictions, the mean error and the percentage of estimations with a mean error of less than 10%were used.
Fourteen formulae provided a mean error lower than 10%. Ten of these formulae allowed estimations within 卤10%of the actual birth weight in more that 65%of predictions. The most accurate formulae in predicting fetal weight were those of Hadlock and Aoki. With our formula, which employs three ultrasound parameters, 73.8%of estimations were valid with a mean error of 10%and 87.9%had an error of less than 15%.
The accuracy of fetal weight estimation by ultrasound is limited and may improve with the new formula adjusted to our population.