Fractional Thigh Volume by Three Dimensional Ultrasonography for Birth Weight Prediction

Abstract

Accurate estimation of fetal weight is most important when dealing with high-risk populations, particularly when dealing with the two extremes of birth weight. Estimated fetal weight is taken into consideration when making clinical decisions involving induction or delay of labor and method of delivery (Nahum et al., 2003). Limiting the potential complications associated with birth of both small and excessively large fetuses requires that accurate estimation of fetal weight occur in advance of delivery. During the last 30 years, sonographic assessment of the fetus and estimation of its weight have become a part of routine practice. Many formulas have been published, most of them involving combinations of several biometric parameters. Generally, these methods have insignificant systemic errors, but random errors of less than approximately 7% are rarely reported (Siemer et al., 2009). To date, 2-dimensional ultrasound (2-D US) becomes an essential tool for fetal weight evaluation. Many birth weight formulas are consisting of common fetal growth indices derived from two dimensional ultrasound such as BPD (biparietal diameter), HC (head circumference), AC (abdominal circumference), and FL (femur length) (Callen,2007). None of these formulas took soft tissue into account. The arrival of the 3D US has allowed a more accurate volumetric assessment of several fetal organs, for an earlier and more precise diagnosis of fetal growth and developmental deviations. (Edward et al, 2007) Fractional limb volume can now be added to 2D sonographic measurements of the head and trunk to improve the precision of estimated fetal weight. The combination of fractional limb volume and 2D fetal measurements provides a soft tissue component to a weight estimation procedure for a more robust assessment of fetal nutritional status. A major step towards translation of these results into clinical practice will depend on the development of automated fractional limb volume measurements that are easily calculated using commercially available computer software. (Srisantiroj et al, 2009) The present study was conducted at Ain Shams University Maternity and Women's Hospital, including 120 pregnant patients in a period from January 2014 till August 2014.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. Both two-dimensional and three-dimensional ultrasound examinations were performed to the study group, most patients were admitted for an elective cesarean delivery for obstetric indication. All fetuses were delivered within 4 days after the ultrasound examination. The current study compared Hadlock formula, which represents use of 2D US using BPD, FL & AC in predicting fetal birth weight and 3D US using different formulas that involve fractional TVol.