title: Nomograms of the fetal neck circumference and area throughout gestation.
abstract: OBJECTIVE
  The purpose of this study was to create reference range nomograms of the axial fetal neck circumference (FNC) and fetal neck area (FNA) throughout gestation.
  
  
  METHODS
  This prospective cross-sectional study involved pregnant patients between 14 and 40 weeks' gestation. Inclusion criteria consisted of well-established dates (confirmed by early sonography) and nonanomalous singleton fetuses with intact fetal membranes. Sonographic measurements included biparietal diameter, head circumference, abdominal circumference, femur length, humerus length, transcerebellar diameter, and sonographically estimated fetal weight. Axial FNC and FNA values were calculated as means of 3 separate measurements. The 5th, 50th, and 95th percentiles were estimated at each week of gestational age (GA) by least squares regression for the mean and SD of the FNC and FNA as functions of GA. R(2) and associated P values for the relationships between the FNC, FNA, and other sonographic biometric measurements were calculated.
  
  
  RESULTS
  The study included 720 consecutive patients. The mean maternal age +/- SD was 27.3 +/- 6.6 years; median gravidity, 3 (range, 1-13); and median parity, 1 (range, 0-10). The following equations were devised: mean FNC (centimeters) = -11.85 + 1.687 x GA (weeks) -0.043 x GA(2) + 0.0004951 x GA(3); SD(FNC) = 3.15 - 0.3823 x GA + 0.01733 x GA(2) - 0.0002179 x GA(3); mean FNA (square centimeters) = 37.29 - 7.0 x GA + 0.4717 x GA(2) - 0.01245 x GA(3) + 0.0001222 x GA(4); and SD(FNA) = 7.08 - 0.9413 x GA + 0.04135 x GA(2) - 0.0004829 x GA(3). Both the FNC and FNA correlated significantly and strongly with biparietal diameter, head circumference, abdominal circumference, humerus length, femur length, transcerebellar diameter, and sonographically estimated fetal weight.
  
  
  CONCLUSIONS
  Current nomograms of the axial FNC and FNA throughout gestation have been provided.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, 450 Clarkson Ave, Box 24, Brooklyn, NY 11203, USA. dmsherer@aol.com
authors.forename: David M
authors.initials: DM
authors.lastname: Sherer
authors.forename: Margarita
authors.initials: M
authors.lastname: Sokolovski
authors.forename: Mudar
authors.initials: M
authors.lastname: Dalloul
authors.forename: Emil
authors.initials: E
authors.lastname: Dib
authors.forename: John C
authors.initials: JC
authors.lastname: Pezzullo
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Osho
authors.forename: Ovadia
authors.initials: O
authors.lastname: Abulafia
mesh_terms: D000886:Anthropometry / Q000379:methods*; D001830:Body Surface Area; D003198:Computer Simulation; D005865:Gestational Age; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008954:Models, Biological; D009333:Neck / Q000000981:diagnostic imaging* / Q000196:embryology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*