title: Three-dimensional sonographic determination of normal fetal mandibular and maxillary size during the second half of pregnancy.
abstract: OBJECTIVE
  To explore the various ways of obtaining fetal maxillary and mandibular size with three-dimensional (3D) ultrasound, with a view to developing a tool for identifying minor anomalies in the lower facial region.
  
  
  METHODS
  Serial 3D sonographic measurements of the fetal jaws were made in 126 normal singleton pregnancies at 18-34 weeks of gestation for determination of degree of maxillary and mandibular protrusion, maxillary and mandibular corpus lengths, mid- and lower facial depths and maxillary and mandibular curvature. In a sub study the reproducibility of the measurements was evaluated.
  
  
  RESULTS
  The coefficient of variation in the reproducibility study varied between 7.1 and 10.5%. For all parameters except maxillary and mandibular protrusion, there was a significant gestational age-related increase. Ratios of maxillary/mandibular protrusion, maxillary/mandibular corpus lengths, mid-/lower facial depths and maxillary/mandibular curvature all showed a significant gestational age-related decrease, with the most distinct decrease in the mid-/lower facial depth ratio.
  
  
  CONCLUSIONS
  3D sonographic measurement of the fetal maxilla and mandible demonstrated an acceptable intraobserver variability for all measurements. The mid-/lower facial depth ratio appears to be most valuable in determining abnormal mandibular development.
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center Rotterdam, The Netherlands. NMRoelfsema@hotmail.com
authors.forename: N M
authors.initials: NM
authors.lastname: Roelfsema
authors.forename: W C J
authors.initials: WC
authors.lastname: Hop
authors.forename: J W
authors.initials: JW
authors.lastname: Wladimiroff
mesh_terms: D000328:Adult; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007231:Infant, Newborn; D007568:Jaw / Q000000981:diagnostic imaging / Q000196:embryology* / Q000502:physiology; D008137:Longitudinal Studies; D008445:Maxillofacial Development / Q000502:physiology*; D015588:Observer Variation; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D016216:Ultrasonography, Prenatal / Q000379:methods*