Predicting term birth weight using ultrasound and maternal characteristics.

OBJECTIVES: The aim of the study was to compare an ultrasound-based prediction formula of Shepard, Hadlock, our new equation and equation of Nahum based on maternal characteristics.

STUDY DESIGN: Two groups of 125 (group A) and 130 (group B) healthy term pregnant women were sampled. Standard ultrasonographic measurements were performed and maternal characteristics recorded. A new birth weight equation was developed by multiple stepwise regression analysis from the group A data and then compared to the different birth weight prediction equations of Hadlock, Shepard and Nahum on group B.

RESULTS: New prediction equation: log(10) EFW=0.64041xBPD-0.03257xBPD(2)+0.00154xACxFL. Our new (Halaska) and Hadlock's ultrasound estimations are comparable. Both equations are superior to Shepard and Nahum's equations. The Nahum equation is comparable to the Shepard estimation. Halaska equation tends to have the highest overall accuracy, Hadlock's estimation predicts better fetuses over 4000g, but this needs to be further validated.

CONCLUSIONS: The Halaska and Hadlock's estimations are comparable to one another; the Nahum equation is comparable to Shepard's and can be used as simple, inexpensive and approximative estimate.