title: Fetal thyroid in two-dimensional ultrasonography: nomograms according to gestational age and biparietal diameter.
abstract: OBJECTIVE
  To establish fetal thyroid nomograms based on gestational age and biparietal diameter and to compare obtained results with previously published data.
  
  
  METHODS
  A cross-sectional study of 241 healthy pregnant women at 14-38 week of gestation was undertaken. Exclusion criteria were: known maternal thyroid or systemic disease, unknown date of last menstrual period, multiple pregnancy and fetal malformations. Fetal thyroid diameter (FTD), circumference (FTC) and area (FTA) were measured by two-dimensional ultrasonography and plotted against gestational age (GA) and biparietal diameter (BPD).
  
  
  RESULTS
  FTD, FTC and FTA increased logarithmically to GA and BPD. Fetal thyroid measurements as a function of GA were expressed by logarithmic formulas: ln(FTD)=3.6025-23.0315/GA, ln(FTC)=4.6227-22.8003/GA, ln(FTA)=6.6303-45.0831/GA. The following logarithmic formulas were obtained for fetal thyroid measurements according to BPD: ln(FTD)=3.4068-45.4271/BPD, ln(FTC)=4.4271-44.8359/BPD, ln(FTA)=6.2390-88.4408/BPD. There were highly significant correlations between thyroid measurements and GA or BPD: r=0.87-0.90, p<0.00001.
  
  
  CONCLUSIONS
  We have established age-dependent and age-independent nomograms of fetal thyroid. These nomograms will enable prenatal diagnosis in fetuses at risk of thyroid disorders.
authors.affiliation: Department of Endocrinology, Medical Center of Postgraduate Education, Warsaw, Poland. malgietka@vp.pl
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Gietka-Czernel
authors.forename: Marzena
authors.initials: M
authors.lastname: Dębska
authors.forename: Piotr
authors.initials: P
authors.lastname: Kretowicz
authors.forename: Romuald
authors.initials: R
authors.lastname: Dębski
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zgliczyński
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging; D005865:Gestational Age; D006801:Humans; D007455:Iodine / Q000172:deficiency; D049451:Nomograms; D011044:Poland; D011247:Pregnancy; D012016:Reference Values; D013959:Thyroid Diseases / Q000000981:diagnostic imaging; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000196:embryology*; D016216:Ultrasonography, Prenatal
chemical_list: D007455:Iodine