A Comparison of Ultrasound Methods of Fetal Weight Prediction in the Third Trimester

Abstract The antenatal ultrasound measurement of the fetal parameters of abdomen circumference, head circumference and the product of crown‐rump length and abdomen cross sectional area or fetal “volume”, were compared with the birthweights of newborn delivered within 72 hours of measurement. Birthweight was highly correlated with head circumference (r = 0.87), abdomen circumference (r = 0.96) and fetal “volume” (r = 0.95). Fitted linear regression equations were calculated relating birthweight to the three ultrasound factors. For abdomen circumference and fetal “volume” the residual standard deviation of birthweight values about the regression line was 250 g. A linear combination of abdomen circumference and fetal “volume”, and abdomen circumference and head circumference values was better than abdomen circumference alone to predict birthweight There was no clinical advantage in using fetal “volume” over abdomen circumference alone to predict birthweight.