title: Maternal smoking, obesity and male fetal sex predispose to a large nuchal translucency thickness in healthy fetuses.
abstract: OBJECTIVE
  Our aim was to evaluate the effect of fetal sex, smoking and body mass index (BMI) on nuchal translucency (NT).
  
  
  METHODS
  We analyzed data from 7,357 women with a normal singleton live birth outcome with information on smoking, BMI and sex of the infant. NT measurements were converted to multiples of the median (MoM(NT)) using a previously reported linear regression analysis.
  
  
  RESULTS
  The odds ratio (OR) for MoM(NT) >95th centile was 1.5 (95% CI 1.2-1.9) for smokers compared to nonsmokers and 1.4 (95% CI 1.1-1.7) for male fetuses compared to female fetuses. Obese women (BMI ≥30) had an increased OR for a large NT of 1.7 (95% CI 1.2-2.6) compared to normal weight women. Obese smokers carrying a male fetus had an OR of 4.2 (95% CI 1.7-10.1) of a MoM(NT) >95th centile compared to normal weight nonsmoking women with a female fetus. The effects of smoking, obesity status and fetal sex were independent of each other.
  
  
  CONCLUSIONS
  Smoking, obesity and male sex are associated to a MoM(NT) >95th centile. This may affect screening performance and entail unnecessary anxiety in these women. Further investigations, including fetuses with adverse outcome, are needed.
authors.affiliation: Department of Fetal Medicine and Ultrasound, Rigshospitalet and University of Copenhagen, Denmark. linerode @ dadlnet.dk
authors.forename: L
authors.initials: L
authors.lastname: Rode
authors.forename: C
authors.initials: C
authors.lastname: Ekelund
authors.forename: N G
authors.initials: NG
authors.lastname: Pedersen
authors.forename: K R
authors.initials: KR
authors.lastname: Wøjdemann
authors.forename: M
authors.initials: M
authors.lastname: Christiansen
authors.forename: K
authors.initials: K
authors.lastname: Sundberg
authors.forename: A
authors.initials: A
authors.lastname: Tabor
mesh_terms: D015992:Body Mass Index; D005260:Female; D047109:Fetal Development; D006801:Humans; D008297:Male; D048208:Nuchal Translucency Measurement; D009765:Obesity / Q000150:complications*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*