title: Impact of gestational age on nuchal fold thickness in the second trimester.
abstract: OBJECTIVE
  The purpose of this study was to establish gestational age (GA)-specific nomograms for nuchal fold thickness between 16 and 24 weeks.
  
  
  METHODS
  This retrospective cross sectional study included 32,207 women who underwent a second-trimester anomaly scan at the Fetal Care Center of National University Hospital from January 2005 to April 2011. Nomograms were plotted for nuchal fold thickness at each gestation to study its variation with GA.
  
  
  RESULTS
  Nuchal fold thickness increased with GA in a linear manner from 3.13 ± 0.68 mm (mean ± SD) at 16 weeks to 5.08 ± 0.76 mm at 24 weeks. The 95th percentile measurement at 24 weeks remained less than 6 mm.
  
  
  CONCLUSIONS
  A threshold of 6 mm appears to be appropriate for the diagnosis of a thick nuchal fold even for gestations between 20 and 24 weeks.
authors.affiliation: MRCOG, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074. chanchalsngh@gmail.com.
authors.forename: Chanchal
authors.initials: C
authors.lastname: Singh
authors.forename: Arijit
authors.initials: A
authors.lastname: Biswas
mesh_terms: D017677:Age Distribution; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D048208:Nuchal Translucency Measurement / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data*; D009929:Organ Size; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000502:physiology*; D012016:Reference Values; D012846:Singapore / Q000453:epidemiology
keywords: aneuploidy screening; nuchal fold thickness; obstetric ultrasound; second trimester; sonography