title: Transient neonatal hyperthyrotropinemia is a risk factor for developing persistent hyperthyrotropinemia in childhood with repercussion on developmental status.
abstract: OBJECTIVE
  Transient neonatal hyperthyrotropinemia (TNH) is defined as a neonatal abnormality of thyroid function, which reverts to normal at re-examination after 2 weeks of life. The thyroid function of these infants has not been sufficiently studied in terms of the risk of developing persistent hyperthyrotropinemia (PH) in later childhood and its impact on growth and development.
  
  
  METHODS
  A prospective cohort study included all babies born in our hospital between 2001 and 2006 and screened for hypothyroidism, whose thyroid function was re-examined 6 years later. Exclusion criteria included the following conditions: preterm birth, birth weight <2500 g, Down's syndrome, descendants of mothers with immune thyroid disease, congenital malformations, cardiac, renal, hepatic, and metabolic diseases, and steroid or dopamine medication. The variables included are TSH and thyroxine at neonatal screening and 6 years later. Main outcomes are the risk of developing PH in childhood, linear growth, and development using Parents' Evaluation of Developmental Status (PEDS).
  
  
  RESULTS
  Out of 5040 normal-term newborns, 301 (6.0%, 95% CI 5.3-6.6%) have TSH ≥10 mU/l (TNH). Six years later, we re-examined 65 randomly selected children with TNH and 185 controls. In the TNH cohort, we found six out of 65 children (9.2%, 95% CI 1.4-17.0%) with PH (TSH ≥6.4 mU/l), and three out of 185 (1.6%, 95% CI 0.3-4.7%) among controls, relative risk 5.7 (95% CI 1.5-22.1), P=0.0114. TSH and developmental delay were found to be significantly higher in the TNH cohort (4.7±1.3 mU/l vs 2.1±0.5 mU/l, P<0.0001 and 15/65 (23%, 95% CI 12-34.1) vs 21/185 (11.3%, 95% CI 6.5-16.2) P=0.0348).
  
  
  CONCLUSIONS
  Newborns with TNH have a higher risk of developing PH in childhood, with repercussion on developmental status.
authors.affiliation: Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina ecuestas@hospitalprivadosa.com.ar.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Cuestas
authors.affiliation: Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Gaido
authors.affiliation: Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina Department of Pediatrics and NeonatologyClinical Biochemistry DepartmentHospital Privado (IUCBC), Avenida Naciones Unidas 346, 5016 Cordoba, ArgentinaFaculty of Medical SciencesFaculty of Chemical SciencesNational University of Cordoba, Cordoba, ArgentinaHealth Sciences Research Institute (INICSA)National Council of Scientific and Technical Research (CONICET), Cordoba, Argentina.
authors.forename: Raúl Horacio
authors.initials: RH
authors.lastname: Capra
mesh_terms: D017668:Age of Onset; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000151:congenital* / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000453:epidemiology; D008297:Male; D015997:Neonatal Screening; D012307:Risk Factors; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D013974:Thyroxine