Accuracy of Three-Dimensional Sonographic Thigh Volume Versus Two-Dimensional Sonographic Formula At Term In Detection Of Birth Weight

Abstract

Abnormal fetal growth pattern is associated with an increased risk for neonatal morbidity and mortality (Dashe et al., 2000), and it could be a determining factor in the management of an obstetric case (Yang et al., 2011). Ultrasonographic estimated fetal weight (EFW) has been used to identify growth abnormalities. Prediction of EFW before delivery may be achieved through the measurement of abdominal circumference (AC) in combination with other biometric measurements, such as biparirtal diameter (BPD), head circumference (HC) and/or femur length (FL) (Lee et al., 2009 The commonly used formulas (Shepard et al., 1982; Hadlock et al., 1984) for estimating fetal size, depending on fetal biometry measurements using two-dimensional (2D) ultrasound, are not highly accurate and few of these formulas considered soft-tissue thickness (Yang et al., 2011). Several investigators have proposed estimating fetal size through soft tissue evaluation of the fetal thigh thickness or circumference (Scioscia et al., 2008), Because it is well documented that the fetal thigh volume (ThV) is related to fetal growth and nutritional status (Song et al., 2000; Lee et al., 2001), many studies of predicting fetal weight have used ThV as a predictor to fetal growth and weight, as well as nutritional status, and have proven that fetal ThV is relevant to fetal growth, weight and nutritional status (Chang et al., 2003). As three-dimensional (3D) ultrasonography has the potential for allowing more accurate volume measurements compared with 2D ultrasonography, several investigators have measured fetal limb volumes to predict BW by 3D ultrasonography (Lee et al., 2001). Measurement of fetal ThV using 3D ultrasound has contributed to significant improvements in the accuracy of BW estimation (Chang et al., 1997; Liang et al., 1997; Schild et al., 2000). It has been demonstrated that formulas derived from such volume measurements allow the prediction of BW with absolute percentage errors of less than 6% (Beninni et al., 2010a). Previous studies comparing the accuracy of 3D volume-derived equations with that of the traditional 2D measurement models and reported that the prediction of BW using fetal limb volumetry is more precise than that obtained using conventional 2D ultrasound parameters (Chang et al., 1997; Liang et al., 1997; Schild et al., 2000; Lee et al., 2001; Lee et al., 2009). The aim of this study is to assess the accuracy of three dimensional ultrasonography measurement of fetal thigh volume in prediction of fetal weight in comparison to the conventional two dimensional Hadlock formula. The present study was conducted at Ain Shams University Maternity and Women's Hospital, including 44 pregnant between 37-41weeks of gestation patients in a period from June till December 2015. The study was performed in cooperation with the Feto-Maternal Unit for ultrasound assessment in the university maternity hospital at Ain-Shams faculty of medicine after respecting certain inclusion and exclusion criteria