title: Nomograms for the sonographic measurement of the fetal philtrum and chin.
abstract: OBJECTIVE
  To generate nomograms for the sonographic measurement of the fetal philtrum and chin during pregnancy.
  
  
  METHODS
  A prospective, cross-sectional study in normal singleton pregnancies.
  
  
  METHODS
  One hundred and fifty-three fetuses between 13 and 42 weeks of gestation were studied.
  
  
  METHODS
  The philtrum was measured from the base of the columella to the upper lip. The chin was measured from the tip of the lower lip to the skin under the lower tip of the mandible. Predictive models were evaluated to generate graphic description of the 5th, 50th and 95th centiles for the fetal philtrum and chin.
  
  
  RESULTS
  Fetal philtrum length increased with gestational age. The regression equation for the philtrum length (y) according to gestational age in weeks (x) is best predicted by the S-curve (Gompertz) model, as described by the following equation: y = exp(a + b/x), where a = 2.778577, and b = -23.476723 (R(2) = 85.3%, p < 0.0001). The fetal chin length increased with gestational age. The regression equation for the mean chin length (y) according to gestational age in weeks (x) is best predicted by the S-curve model as described in the following equation. y = exp(a + b/x), where a = 3.7922, b = -28.043, (R(2) = 89.0%, p < 0.0001).
  
  
  CONCLUSIONS
  The nomograms generated in this study for the fetal philtrum and chin during pregnancy can be used in confirming subjective impression of facial dysmorphism.
authors.affiliation: Ultrasound Unit, Department of Obstetrics and Gynecology, Lis Maternity Hospital, Tel Aviv, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Gull
authors.forename: Igal
authors.initials: I
authors.lastname: Wolman
authors.forename: Paul
authors.initials: P
authors.lastname: Merlob
authors.forename: Ariel J
authors.initials: AJ
authors.lastname: Jaffa
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Lessing
authors.forename: Yuval
authors.initials: Y
authors.lastname: Yaron
mesh_terms: D002680:Chin / Q000000981:diagnostic imaging / Q000196:embryology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008046:Lip / Q000000981:diagnostic imaging / Q000196:embryology*; D008844:Micrognathism / Q000000981:diagnostic imaging; D049451:Nomograms; D011247:Pregnancy; D012044:Regression Analysis; D016216:Ultrasonography, Prenatal