ABSTRACT
OBJECTIVE: To compare the accuracy of three-dimensional (3-D) ultrasound-assessed fetal thigh volumetry in predicting birth weight with that of other commonly used formulas composed of biparietal dimeter (BPD), abdominal circumference (AC), and femur length (FL) by two-dimentional (2-D) ultrasonography. METHODS: From May 1999 to February 2000 we performed a prospective study of ultrasonography on 100 pregnant women. We assessed the thigh volume of 100 fetuses using 3-D ultrasonography. Meanwhile their BPD, AC, and FL were measured by 2-D ultrasonography. All infants were delivered within 48 hours after the ultrasound examinations. RESULTS: The thigh volume assessed by 3-D ultrasonography was highly correlated with birth weight (r=0.414, n=100, p<0.0001). The 3-D formula had small mean values of absolute mean error (gm) (64.26), absolute mean error (%) (10.20+/-0.80). As well, the 2-D formulas had similar mean values. However, no significant differences in predicting birth weight were found between 3-D formula and 2-D formulas. CONCLUSION: The 3-D ultrasound method assessed by thigh volume showed better accuracy in predicting birth weight than 2-D methed. Further studies may be needed to confirm our conclusions.