Combined 3-D Fractional thigh volume with 2-D Sonographic biometry for estimating fetal weight

Abstract

Objective:To generate a new equation for birthweight estimation in the Thai population using fractional thigh volume (Tvol) with a conventional two dimensional ultrasound (2D US).Materials and methods:A prospective, cross-sectional study was conducted. 123 normal fetuses from 37-42 weeks of gestation were examined within 48 hours before delivery. 2D US was performed for conventional fetal biometry and Tvol was collected by three dimensional ultrasound (3D US). The ultrasound was performed by the author who is an US trained, second year obstetric resident. Intra-observer reliability was analyzed using intraclass correlation coefficient (ICC). Stepwise regression analysis was used to generate a new equation.Results:ICC 0.994 for Tvol has showed good intra-observer reliability in this study. Two strong biometries correlated with birthweight are Tvol (r=0.96) and biparietal diameter (r=0.044). Birthweight estimation equation from the study was birthweight (grams) = 1241.285 + 22.908 Tvol + 43.741 BPD (r2 = 0.949).Conclusion: The Tvol fetal biometry showed a good correlation with fetal birthweight and it could be combined with biparietal diameter to estimate fetal weight.

Keywords

• Fractional thigh volume
• 2-D ultrasonographic biometry
• estimated fetal weight