title: Characteristics of Delayed Thyroid Stimulating Hormone Elevation in Neonatal Intensive Care Unit Newborns.
abstract: OBJECTIVE
  To elucidate the incidence, clinical characteristics, and short-term outcome of delayed thyroid stimulating hormone (TSH) elevation (dTSH) in a large cohort of newborns admitted to the neonatal intensive care unit.
  
  
  METHODS
  Data were gathered from a cohort of 13 201 newborns admitted to the neonatal intensive care unit born between January 1, 2008, and October 31, 2014, who underwent TSH measurements because of low T4 levels on the second screen. The data from the newborn screening program included gestational age, birth weight (BW), T4 levels, and short-term outcome.
  
  
  RESULTS
  Of 13 201 newborns, 333 (1:40) presented with dTSH (TSH >15 IU/L). dTSH had a peak proportion at gestational age of 37-39 weeks, and 66% of the patients had BW >1500 g. T4 levels in the 333 patients were negatively correlated with TSH levels (R = -0.505; P < .001), and significantly lower than levels in the other newborns: 5.9 ± 2.8 vs 7.6 ± 1.7 µg/dL; P < .001. TSH levels in dTSH newborns were already higher on the initial screen compared with the other newborns: 8.3 ± 5.2 vs 4.2 ± 3.7 IU/L; P < .001. Fifty-eight percent of 193 patients with dTSH were started on levothyroxine treatment.
  
  
  CONCLUSIONS
  dTSH has a higher incidence than previously reported, especially among newborns with BW >1500 g. Relatively high TSH and low T4 levels on the initial and second screen respectively are predictors for dTSH. Levothyroxine treatment is required in most cases.
authors.affiliation: Pediatric Endocrinology Unit, Kaplan Medical Center, Rehovot, Israel; Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: amnon.zung@gmail.com.
authors.forename: Amnon
authors.initials: A
authors.lastname: Zung
authors.affiliation: Gamidor Diagnostics, Petach Tikva, Israel.
authors.forename: Arie
authors.initials: A
authors.lastname: Yehieli
authors.affiliation: The National Center for Newborn Screening, Ministry of Health, Tel-HaShomer, Israel.
authors.forename: Ayala
authors.initials: A
authors.lastname: Blau
authors.affiliation: The National Center for Newborn Screening, Ministry of Health, Tel-HaShomer, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Almashanu
mesh_terms: D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis*; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D015997:Neonatal Screening / Q000379:methods*; D013972:Thyrotropin / Q000097:blood*
chemical_list: D013972:Thyrotropin
keywords: levothyroxine; low birth weight; newborn screening