title: Fetal trunk and head volume measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal pregnancies.
abstract: OBJECTIVE
  To establish the relationship between fetal trunk and head volume measured by three-dimensional (3D) ultrasound and gestational age at 11 + 0 to 13 + 6 weeks of gestation.
  
  
  METHODS
  The fetal trunk and head volume were measured using 3D ultrasound in 417 chromosomally normal fetuses from singleton pregnancies at 11 + 0 to 13 + 6 (median, 12 + 0) weeks of gestation. Regression analysis was used to determine the significance of the association between fetal volume and gestational age. The Bland-Altman analysis was used to compare the measurement agreement and bias for a single examiner and between different examiners.
  
  
  RESULTS
  The fetal trunk and head volume increased linearly with gestation from a mean of 5.8 mL at 11 + 0 weeks to 33.3 mL at 13 + 6 weeks and 1 SD was 4.4 mL. There was also a significant linear association between fetal volume and crown-rump length (CRL), from a mean of 5.1 mL at a CRL of 45 mm to 37.5 mL at a CRL of 84 mm and 1 SD was 2.7 mL. However, within this gestational range, a doubling in CRL, from a mean of 48 mm at 11 + 0 weeks to 79 mm at 13 + 6 weeks, was associated with a 5-6-fold increase in fetal volume. The mean difference in fetal volume between paired measurements by the same sonographer was -0.87 mL (95% limits of agreement, -2.31 to 4.05 mL) and the mean difference between paired measurements by two sonographers was -1.09 mL (-5.49 to 3.32 mL).
  
  
  CONCLUSIONS
  3D ultrasound can provide a reproducible measurement of the fetal trunk and head volume in early pregnancy. At between 11 + 0 and 13 + 6 weeks there is a 5-6-fold increase in fetal volume but only a doubling in CRL.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, UK.
authors.forename: O
authors.initials: O
authors.lastname: Falcon
authors.forename: C F A
authors.initials: CF
authors.lastname: Peralta
authors.forename: P
authors.initials: P
authors.lastname: Cavoretto
authors.forename: S
authors.initials: S
authors.lastname: Faiola
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging / Q000196:embryology*; D000328:Adult; D000886:Anthropometry / Q000379:methods; D002508:Cephalometry / Q000379:methods; D018568:Crown-Rump Length; D005260:Female; D047109:Fetal Development; D005865:Gestational Age; D006257:Head / Q000000981:diagnostic imaging / Q000196:embryology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008875:Middle Aged; D011247:Pregnancy; D012016:Reference Values; D013909:Thorax / Q000000981:diagnostic imaging / Q000196:embryology*; D016216:Ultrasonography, Prenatal / Q000379:methods*