title: Clinical and ultrasound estimation of birth weight prior to induction of labor at term.
abstract: OBJECTIVE
  To assess and compare the accuracy of clinical and sonographic fetal weight estimation in predicting birth weight prior to induction of labor.
  
  
  METHODS
  In a prospective study of 262 women immediately prior to induction of labor, the fetal weight was estimated clinically by both the doctor (DR EFW) and the woman herself (WM EFW). A transabdominal scan was then performed to estimate the fetal weight sonographically using two different formulae-Shepard (SHEP EFW) and Hadlock (HAD EFW). The four estimated fetal weights were compared with the actual birth weight.
  
  
  RESULTS
  The mean percentage error was - 1.9 +/- 9.3% for DR EFW, - 3.4 +/- 12.6% for WM EFW, - 2.3 +/- 11.6% for SHEP EFW and - 7.6 +/- 10.6% for HAD EFW. All four EFWs were significantly different from birth weight (t = - 4.7, - 5.5, - 3.5 and - 11.4, respectively, all P < 0.01). The corresponding proportion of the EFWs which were within 10% of birth weight were 71%, 59%, 62% and 42%, respectively. The sensitivity and specificity of detecting a fetus weighing < 3000 g were 56% and 98% for DR EFW, 90% and 89% for WM EFW, 93% and 83% for SHEP EFW and 100% and 76% for HAD EFW. The corresponding values for detecting a fetus weighing > 4000 g were 16% and 99%, 29% and 96%, 48% and 92% and 40% and 94%, respectively.
  
  
  CONCLUSIONS
  Although, in general, clinical estimates of birth weight perform favorably compared with ultrasonographic estimates, ultrasound immediately prior to labor is more accurate at predicting the low- or high-birth-weight fetus.
authors.affiliation: Department of Obstetrics and Gynaecology, University College London Hospitals, London, UK. e.peregrine@ucl.ac.uk
authors.forename: E
authors.initials: E
authors.lastname: Peregrine
authors.forename: P
authors.initials: P
authors.lastname: O'Brien
authors.forename: E
authors.initials: E
authors.lastname: Jauniaux
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D003627:Data Interpretation, Statistical; D005260:Female; D020567:Fetal Weight; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced; D008875:Middle Aged; D009774:Obstetrics / Q000379:methods*; D010173:Palpation / Q000592:standards; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000592:standards*