title: Fetal volume at 11-14 gestational weeks: reference ranges and association with first trimester biochemical and biophysical markers.
abstract: OBJECTIVE
  To establish reference ranges for fetal volume (FV) measured by three-dimensional ultrasound (3D-US) at 11-14 weeks of gestation and to examine the possible association of FV with maternal/pregnancy characteristics and biochemical parameters.
  
  
  METHODS
  Prospective observational study on 240 fetuses at 11-14 weeks. FV was measured by 3D-US using Virtual Organ Computer-Aided Analysis. Pearson correlation coefficient (cc) and regression analysis were used.
  
  
  RESULTS
  FV increased exponentially with crown rump length and was unrelated to maternal weight (cc=-0.137, P=0.071), age (cc=0.009, P=0.899), parity (0.76), smoking status (t-test, P=0.149) and mode of conception (t-test, P=0.8). Z-scores (z) of FV was not associated with z-mean uterine artery pulsatility index (cc=-0.026, P=0.733), log10 multiples of the median (MoM) free beta human chorionic gonadotrophin (cc=0.002, P=0.982), delta value (d) of nuchal translucency (cc=0.072, P=0.331) and d-fetal heart rate (cc=0.009, P=0.902), z-FV was significantly positively correlated with log10 MoM pregnancy associated plasma protein-A (PAPP-A; regression coefficient=1.420976, R2=0.0957, P<0.0001).
  
  
  CONCLUSIONS
  FV is strongly related to PAPP-A even after adjustment for crown rump length with a mechanism unrelated to placental perfusion. FV is independent of the vast majority of first trimester parameters; hence, it is a promising marker of early fetal growth.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papastefanou
authors.forename: Dimitra
authors.initials: D
authors.lastname: Kappou
authors.forename: Athena P
authors.initials: AP
authors.lastname: Souka
authors.forename: Charalambos
authors.initials: C
authors.lastname: Chrelias
authors.forename: Charalambos
authors.initials: C
authors.lastname: Siristatidis
authors.forename: Athanasios
authors.initials: A
authors.lastname: Pilalis
authors.forename: Demetrios
authors.initials: D
authors.lastname: Kassanos
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood / Q000502:physiology*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011446:Prospective Studies; D011673:Pulsatile Flow; D012016:Reference Values; D012044:Regression Analysis; D016216:Ultrasonography, Prenatal / Q000379:methods; D055988:Uterine Artery / Q000502:physiology
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A; C579283:PAPPA protein, human