title: Fetal mid-thigh soft-tissue thickness: a novel method for fetal weight estimation.
abstract: OBJECTIVE
  To derive a novel formula for fetal weight estimation utilizing the linear measurement of mid-thigh soft-tissue thickness (STT).
  
  
  METHODS
  300 women, with singleton uncomplicated pregnancy, were included in a prospective cross-sectional study. The study included four consecutive phases: phase (1) validated the original Scioscia's formula, phase (2) derived a novel modified formula for fetal weight estimation, phase (3) validated the novel modified formula, and phase (4) evaluated the agreement between the modified and original formulae.
  
  
  RESULTS
  A statistically significant correlation was found between actual fetal weight (AFW) and various sonographic biometric measurements including mid-thigh STT (r (2) = 0.656, p < 0.001), femur length (FL) (r (2) = 0.573, p < 0.001), bi-parietal diameter (BPD) (r (2) = 0.250, p < 0.001), abdominal circumference (AC) (r (2) = 0.310, p < 0.001), and estimated fetal weight (EFW) using the original Scioscia's formula (r (2) = 0.644, p < 0.001). The modified formula showed a better signed % difference (median = -0.41 %, IQR -1.88 to 2.03) than the original formula (median = -0.51 %, IQR -2.33 to 2.00). It was noted that, using the original formula, 88.7 % of the sample had absolute error below 5 and 98.3 % of the sample had absolute error below 10 %. On the other hand, using the modified formula, 87.3 % of the sample had absolute error below 5 %, while 97.3 % had absolute error below 10 %. The agreement between the two formulae was moderate as 134 patients out of 150 had similar ranking (κ = 0.57).
  
  
  CONCLUSIONS
  Fetal mid-thigh SST is a simple, useful, and easily applicable parameter for fetal weight estimation.
authors.affiliation: Obstetrics and Gynecology Department, Ain Shams University, Cairo, Egypt.
authors.forename: Wessam
authors.initials: W
authors.lastname: Abuelghar
authors.forename: Ahmed
authors.initials: A
authors.lastname: Khairy
authors.forename: Gasser
authors.initials: G
authors.lastname: El Bishry
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ellaithy
authors.forename: Taha
authors.initials: T
authors.lastname: Abd-Elhamid
mesh_terms: D000328:Adult; D001699:Biometry; D001724:Birth Weight; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000196:embryology; D020567:Fetal Weight / Q000502:physiology*; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D015203:Reproducibility of Results; D013848:Thigh / Q000000981:diagnostic imaging* / Q000196:embryology; D016216:Ultrasonography, Prenatal / Q000379:methods*