Prediction of fetal macrosomia by single ultrasonic fetal biometry.

A total of 1,056 fetuses underwent single ultrasonographic measurement of fetal biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and estimated body weight within five days of delivery. The accuracy of these parameters and estimated body weight equations in the prediction of macrosomia (birth weight > or = 4,000 g) was evaluated. With the use of receiver operator characteristic curves, the optimal cutoff value for each parameter with the best sensitivity, specificity and accuracy was selected. BPDs > or = 9.4 cm had the best sensitivity (68.8%), specificity (74.3%), and accuracy (74.1%). ACs > or = 35 cm had the best sensitivity (81.3%), specificity (81.5%), and accuracy (81.5%). FLs > or = 7.0 cm had the best sensitivity (68.8%), specificity (74.5%), and accuracy (74.3%). The estimated body weight equations did not increase the prediction values whether or not FL was included. Both had the same prediction values at > or = 3,700 g, ie, sensitivity (71.9% vs 71.9%), specificity (92.1% vs 93.8%), and accuracy (91.5% vs 93.2%). The results showed AC to be the best single parameter for predicting macrosomia. Combinations of these parameters were better than a single parameter in the prediction of macrosomia.