title: Reference intervals for thyrotropin and thyroid hormones and ultrasonographic thyroid volume during the neonatal period.
abstract: OBJECTIVE
  To determine thyrotropin (TSH) and thyroid hormones reference ranges in healthy term newborns during the neonatal period and to assess the ranges of thyroid volume in newborns using ultrasound scanning.
  
  
  METHODS
  Blood samples were collected from 296 healthy newborns at birth (cord; n: 47) and before feeding on the 1st, 3rd, 5th, 7th, 10th, 14th, and 28th days of life. The levels of TSH and thyroid hormones of the newborns were then compared with results from 50 healthy adults. Thyroid ultrasonography (USG) was performed by the same radiologist on 38 newborns aged 10 days.
  
  
  RESULTS
  TSH and thyroid hormone levels in newborns were statistically higher than those in adults for each day (p < 0.001). Serum TSH concentration on the 1st day of life was higher than at other times (p < 0.001). Mean TSH concentration reverted to the cord level at the 5th or 7th day of life (p > 0.05). TSH levels were no higher than 10 mIU/ml after 2 weeks postnatal age. There was no correlation between hormone levels and Ponderal index (PI), birth weight, gender, or delivery type. Mean thyroid volume was 0.72 ± 0.24 ml (0.36-1.62 ml).
  
  
  CONCLUSIONS
  We conclude that our results are important for CH screening regarding time-dependent changes of TSH and thyroid hormones besides diagnosis of thyroid hypoplasia or hyperplasia.
authors.affiliation: Department of Neonatology, Karadeniz Technical University, Trabzon, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Mutlu
authors.forename: Gülay
authors.initials: G
authors.lastname: Karagüzel
authors.forename: Yüksel
authors.initials: Y
authors.lastname: Alıyazicioğlu
authors.forename: Ilker
authors.initials: I
authors.lastname: Eyüpoğlu
authors.forename: Ayşenur
authors.initials: A
authors.lastname: Okten
authors.forename: Yakup
authors.initials: Y
authors.lastname: Aslan
mesh_terms: D003409:Congenital Hypothyroidism / Q000175:diagnosis; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D008297:Male; D012016:Reference Values; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood*; D014463:Ultrasonography
chemical_list: D013963:Thyroid Hormones; D013972:Thyrotropin