title: Nuchal translucency measurement in normal fetuses.
abstract: OBJECTIVE
  To construct a normal range for the nuchal translucency measurement in chromosomally and phenotypically normal fetuses between 9 and 14 weeks' gestation.
  
  
  METHODS
  The nuchal translucency was measured prospectively in 771 chromosomally normal fetuses of women attending our antenatal clinic or prenatal diagnosis center. The nuchal translucency measurement was expressed as the median and fifth, 25th, 75th, and 95th percentiles according to completed weeks of gestation based on ultrasound measurements.
  
  
  RESULTS
  The median nuchal translucency measurement increased from 0.7 mm at 10 weeks' gestation to 1.5 mm at 13 weeks. A nuchal translucency measurement greater than 2.5 mm was found in 4.6% of the fetuses at 10 weeks' gestation; the incidence increased to 8.7% at 14 weeks.
  
  
  CONCLUSIONS
  In normal fetuses, there is a physiologic variation in the nuchal translucency measurement between 9 and 14 weeks' gestation. The calculation of risk for trisomies based on this measurement should take this variation into account. The adoption of a gestational age-dependent cutoff point, based on the deviation of a given measurement from the median, may reduce the number of false-positive test results requiring invasive procedures for karyotyping.
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Pajkrt
authors.forename: C M
authors.initials: CM
authors.lastname: Bilardo
authors.forename: J M
authors.initials: JM
authors.lastname: Van Lith
authors.forename: B W
authors.initials: BW
authors.lastname: Mol
authors.forename: O P
authors.initials: OP
authors.lastname: Bleker
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D008875:Middle Aged; D009333:Neck / Q000196:embryology*; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D016216:Ultrasonography, Prenatal