title: Statistical limits in sonographic estimation of birth weight.
abstract: OBJECTIVE
  The accuracy of sonographic estimation of birth weight (EBW) is compromised by the precision of the biometrical measurements and the quality of the algorithms. This prospective study was to evaluate technical aspects to derive new equations for the EBW.
  
  
  METHODS
  Three consecutive phases were carried out (1) to recruit a homogenous population, (2) to derive eight new algorithms using a multiple stepwise mathematical/statistical method, and (3) to test the accuracy of the developed equations. Only those patients with a singleton pregnancy who delivered within 48 h from the scan were considered for the analysis.
  
  
  RESULTS
  The study population was made of 473 women. Four polynomial, two square root and two logarithmic algorithms were derived from a balanced study group of 200 women selected from the original study population. These formulas were subsequently applied and compared between them and showed a significant correlation with birth weight (p < 0.0001) and satisfactory statistical performances (r > 0.9), nevertheless they performed similarly to other equations previously published.
  
  
  CONCLUSIONS
  The present findings define better the limitations associated with the intrinsic properties of algorithms and highlight that the possibility to improve the precision of sonographic measurements remains the only point at issue to increase the accuracy in the prediction of birth weight.
authors: Department of Obstetrics and Gynecology, Sacro Cuore Don Calabria General Hospital, Via Don A. Sempreboni, 5, 37024, Negrar, VR, Italy, marcoscioscia@gmail.com.
authors: Marco
authors: M
authors: Scioscia
authors: Floriano
authors: F
authors: Scioscia
authors: Gaetano
authors: G
authors: Scioscia
authors: Stefano
authors: S
authors: Bettocchi
mesh_terms: D000328:Adult; D000465:Algorithms; D001699:Biometry; D001724:Birth Weight / Q000502:physiology*; D005260:Female; D020567:Fetal Weight / Q000502:physiology*; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*