ROLE OF VOLUME(THREE DIMENSIONAL) ULTRASOUND IN ESTIMATION OF FETAL WEIGHT IN APPROPRIATE AND INAPPROPRIATE FETAL GROWTH

Abstract

This observational prospective study was approved by the council of the gynecology and obstetric department 2009 to evaluate the role of volume (3D) ultrasound as a new method for more accurate estimation of fetal weight than conventional 2D ultrasound.
Research methodology: One hundred and thirty-five women prospectively underwent two-dimensional and three-dimensional ultrasonography within 7 days of delivery. Birth weights (BWs) ranged from 1700 to 4550 g. Fetal measurements were extracted using volume datasets for biparietal diameter, abdominal circumference, femur diaphysis length, and fractional thigh volume. Fractional limb volumes were manually traced from a central portion of the femur diaphysis. Median percentage differences were calculated for EFW. The sensitivity of EFW within 10% of BW were calculated for the following formulas Hadlock (AC), Hadlock (BPD, AC, FDL), Tvol, Lee1and Lee 2.
Results: Ultrasound scans were performed between 30 and 41weeks’ menstrual age. Optimal model sensitivity (87.7%) resulted from using a combination of biparietal diameter, abdominal circumference and fractional thigh volume (Lee2). The precision of this model was superior to results obtained using a Hadlock model (83.1%), although accuracy of these predictions was slightly decreased by decreased aminiotic fluid index and placental anterior position. For all fetuses, the prediction model that incorporated fractional thigh volume except for model (Tvol) correctly classified a greater proportion of EFW within 10% of BW when compared with the Hadlock model.
Conclusion: Fractional thigh volume can be added to two-dimensional sonographic measurements of the head and trunk to improve the precision of fetal weight estimation. This approach permits the inclusion of soft tissue development as part of a weight estimation procedure.
Keywords: fetal weight, volume ultrasound, 3D ultrasound; birth weight, fractional thigh volume, 2Dultrasound.