title: Correlation of nuchal translucency and thyroxine at 11-13 weeks of gestation.
abstract: OBJECTIVE
  Nuchal translucency (NT) thickness is one of the major screening markers during the first trimester that could be influenced by several factors. Here, we investigated the association between NT thickness and thyroid related hormones.
  
  
  METHODS
  NT thickness was measured with transabdominal ultrasound in 643 pregnant women between 11 and 13 weeks of gestation. Maternal thyroxine (T4), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) were evaluated. Bivariate correlations were assessed and thyroid profile was subcategorized with regard to the calculated reference ranges.
  
  
  RESULTS
  An inverse relation was found between serum levels of maternal T4 with NT thickness (r = -0.128, p = 0.001) and CRL (r = -0.168, p < 0.001). TSH and hCG were also found to be correlated (Spearman's correlation coefficient = -0.092, p = 0.019). Prevalence of maternal hypothyroidism and subclinical hypothyroidism were 1.1% and 3.7%, respectively.
  
  
  CONCLUSIONS
  Thyroid function tests are found to independently influence NT measurements in the first trimester. Assessment of hormones such as thyroxine could optimize the interpretation of screening tests for pathological conditions during pregnancy.
authors.affiliation: Maternal-Fetal & Neonatal Research Center and Breast Feeding Research Center, Tehran University of Medical Sciences , Tehran , Iran .
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Hantoushzadeh
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Tara
authors.forename: Bahram
authors.initials: B
authors.lastname: Salmanian
authors.forename: Mohammad-Hadi
authors.initials: MH
authors.lastname: Gharedaghi
authors.forename: Khadijeh
authors.initials: K
authors.lastname: Nasri
authors.forename: Masoud
authors.initials: M
authors.lastname: Ganjizadeh
authors.forename: Saeed-Reza
authors.initials: SR
authors.lastname: Ghaffari
authors.forename: Ahmad-Reza
authors.initials: AR
authors.lastname: Tahmasebpour
authors.forename: Babak
authors.initials: B
authors.lastname: Farrokhi
authors.forename: Alireza
authors.initials: A
authors.lastname: Abdollahi
authors.forename: Mahdi
authors.initials: M
authors.lastname: Sheikh
authors.forename: Pouya
authors.initials: P
authors.lastname: Javadian
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D007492:Iran; D048208:Nuchal Translucency Measurement / Q000706:statistics & numerical data; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology; D011261:Pregnancy Trimester, First / Q000097:blood*; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood*
chemical_list: D013972:Thyrotropin; D013974:Thyroxine