title: The effects of maternal and fetal parameters on the quality of nuchal translucency measurement.
abstract: OBJECTIVE
  To evaluate the influence of maternal and fetal parameters on the quality of fetal nuchal translucency measurement.
  
  
  METHODS
  This was a prospective study in 227 consecutive pregnant women undergoing nuchal translucency screening by transabdominal sonography. The same well-qualified sonographer performed all the scans and in each case the best-quality image was selected and scored according to an image scoring system (total maximum score, 9). The quality of the image was examined in relation to maternal age, weight, abdominal wall thickness, amniotic sac diameter, posterior uterine wall depth (distance between abdominal wall surface and posterior uterine wall surface), placental location, fetal crown-rump length and nuchal translucency thickness. Correlation coefficients were calculated and stepwise linear regression was used to adjust for confounders and to define the predictors for image score.
  
  
  RESULTS
  The only two parameters that provided a significant independent contribution to the prediction of the image score were posterior uterine wall depth and fetal crown-rump length. Intravariable analysis of these two parameters demonstrated that the cut-off associated with a significant change in the image quality was 80 mm for posterior uterine wall depth (score difference, 1.06; P < 0.001) and 70 mm for crown-rump length (score difference, 0.77; P = 0.001). In the group of women with two values above these cut-off points, an average score decrease of 1.90 (P < 0.001) was observed.
  
  
  CONCLUSIONS
  The quality of fetal nuchal translucency measurement is poorer when the fetal crown-rump length is > 70 mm and the posterior uterine wall depth is > 80 mm.
authors.affiliation: Department of Obstetrics and Gynecology, Barzilai Medical Center, Ben-Gurion University, Ashkelon, Israel. zohav@barzi.health.gov.il
authors.forename: E
authors.initials: E
authors.lastname: Zohav
authors.forename: A
authors.initials: A
authors.lastname: Dunsky
authors.forename: O
authors.initials: O
authors.lastname: Segal
authors.forename: R
authors.initials: R
authors.lastname: Peled
authors.forename: A
authors.initials: A
authors.lastname: Herman
authors.forename: S
authors.initials: S
authors.lastname: Segal
mesh_terms: D018568:Crown-Rump Length; D005260:Female; D006801:Humans; D009333:Neck / Q000196:embryology*; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal