Fetal weight estimation by ultrasonic measurement of abdominal circumference.

The purpose of this study was to compare ultrasonic measurements of fetal abdominal circumference to ultrasonic measurements of fetal biparietal diameter, as a means of estimating fetal body weight. Of 58 fetuses who had abdominal circumferences measured, 48 (82%) of the predicted weights were within 15% of the actual birth weights. Forty-four of the same 58 fetuses had satisfactory biparietal diameter measurements, but only 21 (48%) of the predicted weights were within 15% of the actual birthweights. Ultrasonic measurement of abdominal circumference appears to be a more reliable index of fetal body weight than other currently available techniques.