Fetal weight prediction by thigh volume measurement with three-dimensional ultrasonography.
OBJECTIVE
To evaluate the usefulness and accuracy of a simple method of predicting fetal weight by measuring fetal thigh volume with three-dimensional ultrasonography.


METHODS
In 84 pregnant women, fetuses without structural or chromosomal anomalies were studied prospectively and cross-sectionally. Biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) were measured by two-dimensional ultrasound. Fetal thigh volume was measured by three-dimensional ultrasound, using three cross-sectional images of femur, from proximal, middle, and distal parts of femur diaphysis. Infants were delivered within 48 hours after ultrasound examinations.


RESULTS
Modified thigh volume measurements using three cross-sectional images of femur by three-dimensional ultrasound were correlated strongly with birth weight (R(2) = 0.921, P <.001). Using linear and polynomial regression, we calculated a new best-fit formula: Birth weight (g) = 165.32 + 28.78 x modified thigh volume (mL). The mean and standard deviation of the residual were 121.8 and 110.4, respectively, in three-dimensional formulas, which were significantly smaller than those of two-dimensional formulas.


CONCLUSIONS
Thigh volume measurement using three cross-sectional images of femur by three-dimensional ultrasound was simple, and there was better accuracy with this method than with two-dimensional ultrasound methods for predicting fetal weight during the third trimester of pregnancy.
Song
T B
TB
Department of Obstetrics and Gynecology, Chonnam National University Medical School, Kwangju, South Korea. tbsong@chonnam.chonnam.ac.kr
Moore
T R
TR
Lee
J I
JI
Kim
Y H
YH
Kim
E K
EK
D000328:Adult; D001724:Birth Weight; D001823:Body Composition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D013848:Thigh / Q000000981:diagnostic imaging* / Q000196:embryology*; D016216:Ultrasonography, Prenatal / Q000592:standards*