title: Neonatal screening for congenital hypothyroidism in Mexico: experience, obstacles, and strategies.
abstract: OBJECTIVE
  To report the experience, obstacles, and strategies of screening for congenital hypothyroidism.
  
  
  METHODS
  Newborns in Mexico.
  
  
  METHODS
  Thyroid stimulating hormone (TSH) was measured by enzyme immunoassay using commercial kits in 1,140,364 newborns.
  
  
  RESULTS
  There were 464 positive cases, of whom 299 (64.4%) were girls. 236 (50.9% showed ectopic nodules, 202 (43.5%) thyroid agenesis, 21 (4.5%) dyshormonogenesis, and 5 (1.1%) an unclassified goitre. The false positive rate was 0.024% and there were 11 false negative results. Currently, 600,000 (26%) of the 2,300,000 newborns are screened. This percentage has been increased in recent years by taking samples from cord blood and will be increased further by starting congenital hypothyroidism screening at social security units and by midwives screening infants born at home.
  
  
  CONCLUSIONS
  Mental retardation in infants in developing countries can be reduced by neonatal screening, and carefully planned strategies can steadily extend the benefits of screening.
authors.affiliation: Dirección General de Salud Reproductiva, Secretaría de Salud, Mexico.
authors.forename: M
authors.initials: M
authors.lastname: Vela
authors.forename: S
authors.initials: S
authors.lastname: Gamboa
authors.forename: A
authors.initials: A
authors.lastname: Loera-Luna
authors.forename: B E
authors.initials: BE
authors.lastname: Aguirre
authors.forename: G
authors.initials: G
authors.lastname: Pérez-Palacios
authors.forename: A
authors.initials: A
authors.lastname: Velázquez
mesh_terms: D001800:Blood Specimen Collection / Q000379:methods; D003409:Congenital Hypothyroidism; D005189:False Positive Reactions; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis* / Q000453:epidemiology; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015997:Neonatal Screening / Q000379:methods / Q000458:organization & administration / Q000592:standards; D015995:Prevalence; D017678:Sex Distribution; D013961:Thyroid Gland / Q000002:abnormalities; D013972:Thyrotropin / Q000097:blood
chemical_list: D013972:Thyrotropin