title: Estimation of fetal weight in pregnancies past term.
abstract: BACKGROUND
  The aim of the study was to investigate the accuracy of estimating fetal weight with ultrasound in pregnancies past term, using the eSnurra algorithm.
  
  
  METHODS
  In all, 419 women with pregnancy length of 290 days, attending a specialist consultation at Stavanger University Hospital, Norway, were included in a prospective observational study. Fetal weight was estimated using biparietal diameter (BPD) and abdominal circumference (AC). The algorithm implemented in an electronic calculation (eSnurra) was used to compute estimated fetal weight (EFW). Results were compared with birthweight (BW).
  
  
  RESULTS
  The mean interval between the ultrasound examination and birth was 2 days (SD 1.4). The median difference between BW and EFW was -6 g (CI -40 to +25 g) and the median percentage error was -0.1% (95% CI -1.0 to 0.6%). The median absolute difference was 190 g (95% CI 170-207 g). The BW was within 10% of EFW in 83% (95% CI 79-87%) of cases and within 15% of EFW in 94% (95% CI 92-96%) of cases. Limits of agreement (95%) were from -553 g to +556 g. Using 5% false-positive rates, the sensitivity in detecting macrosomic and small for gestational age fetuses was 54% (95% CI 35-72%) and 49% (95% CI 35-63%), respectively.
  
  
  CONCLUSIONS
  The accuracy of fetal weight estimation was good. Clinicians should be aware of limitations related to prediction at the upper and lower end, and the importance of choosing appropriate cut-off levels.
authors.affiliation: Department of Obstetrics and Gynecology, Stavanger University Hospital, Stavanger, Norway.|National Center for Fetal Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Torbjørn M
authors.identifier: http://orcid.org/0000-0002-3162-9595
authors.initials: TM
authors.lastname: Eggebø
authors.affiliation: Department of Obstetrics and Gynecology, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Olav A
authors.initials: OA
authors.lastname: Klefstad
authors.affiliation: Department of Obstetrics and Gynecology, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Inger
authors.initials: I
authors.lastname: Økland
authors.affiliation: Department of Obstetrics and Gynecology, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Elsa
authors.identifier: http://orcid.org/0000-0002-1368-9105
authors.initials: E
authors.lastname: Lindtjørn
authors.affiliation: National Center for Fetal Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Sturla H
authors.initials: SH
authors.lastname: Eik-Nes
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.|Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway.
authors.forename: Håkon K
authors.initials: HK
authors.lastname: Gjessing
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001724:Birth Weight; D001837:Body Weights and Measures / Q000379:methods; D005260:Female; D005320:Fetal Macrosomia / Q000175:diagnosis; D020567:Fetal Weight; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011273:Pregnancy, Prolonged; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D055815:Young Adult
keywords: Ultrasound; delivery; prenatal diagnosis