title: A longitudinal study of normal fetal femur volume.
abstract: OBJECTIVE
  Fetal femur volume (FV) is a useful marker of skeletal growth. Our objective was to create a normal FV chart in a cohort of healthy pregnant women and to assess FV repeatability.
  
  
  METHODS
  The method used was a prospective, observational study using 3D ultrasound. Low-risk pregnant women underwent serial scans from 14 to 42 weeks. Strict inclusion and exclusion criteria were used in order to remove pathological conditions. Pregnancies were dated by last menstrual period and confirmed by crown-rump length. FV was measured using three linear measurements and a volume equation. Data were analyzed using multilevel modeling. Repeatability was assessed using within-subject coefficients of variation (CV), intraclass correlation coefficients (ICC), and Bland-Altman plots.
  
  
  RESULTS
  A total of 180 women underwent 868 scans, a median of five scans per participant. Median and centile values were presented in the form of curves, regression equations, and table of values per completed week. Intra-observer CV and ICC were 10.5% and 0.977, respectively; interobserver CV and ICC were 16.8% and 0.923.
  
  
  CONCLUSIONS
  This normal FV chart can be used as a prescriptive standard in order to assess fetal skeletal growth. Measurement repeatability is satisfactory for clinical use, but FV has a larger random error than commonly seen with standard 2D biometry.
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology, University of Oxford, UK.
authors.forename: Christos
authors.initials: C
authors.lastname: Ioannou
authors.forename: Ippokratis
authors.initials: I
authors.lastname: Sarris
authors.forename: Raffaele
authors.initials: R
authors.lastname: Napolitano
authors.forename: Eric
authors.initials: E
authors.lastname: Ohuma
authors.forename: M Kassim
authors.initials: MK
authors.lastname: Javaid
authors.forename: Aris T
authors.initials: AT
authors.lastname: Papageorghiou
mesh_terms: D000328:Adult; D001699:Biometry; D015331:Cohort Studies; D018568:Crown-Rump Length; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000196:embryology; D047109:Fetal Development; D005333:Fetus; D005865:Gestational Age; D057238:Growth Charts; D006801:Humans; D008137:Longitudinal Studies; D009929:Organ Size; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000592:standards