Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 10 2014 10 15 752 756 EN Setila Dalili Pediatrics Growth Disorders Research Center, 17 Shahrivar Hospital, Faculty of Medicine, Guilan University of Medical Sciences, Guilan, Iran. Seyed Mahmood Rezvani Health Center, Guilan University of Medical Sciences, Guilan, Iran. Hossein Dalili Department of Pediatrics, Breastfeeding Research Center, Tehran University of Medical Sciences, Tehran, Iran. Zahra Mohtasham Amiri Department of Social Medicine, Faculty of Medicine, Guilan University of Medical Sciences, Guilan, Iran. Hamid Mohammadi Department of Pediatrics, Faculty of Medicine, Shiraz University of Medical Sciences, Fars, Iran. Sahar Abrisham Kesh Health Center, Guilan University of Medical Sciences, Guilan, Iran. Mohammad Hassan Novin Health Center, Guilan University of Medical Sciences, Guilan, Iran. Abdolreza Medghalchi Eye Research Center, Amiralmomenin Hospital, Faculty of Medicine, Guilan University of Medical Sciences, Guilan , Iran. Hajar Gholamnezhad Health Center, Guilan University of Medical Sciences, Guilan, Iran. 2015 10 11 One of the most preventable causes of mental and growth retardation is congenital hypothyroidism (CH). This study tries to investigate growth and mental outcome of patients with CH. Since November 2006 and November 2007 in Guilan province, north of Iran, all neonates who were diagnosed with CH, evaluated for etiology of CH by laboratory follow up, thyroid sonography or scan. Growth and development of patients with CH were compared with healthy children in same age, geographical area, social and economical classes in four years old. Demographic characteristics including height, weight, and head circumference at birth, follow up time (four years old) and IQ (Good enough test) were recorded in questionnaires. Among 28904 screened neonates, 37 patients with CH were diagnosed. Incidence of CH was 1:781 in live births, 20 (54%) in female neonates and 17 (46%) in male neonates. The incidences of permanent and transient hypothyroidism were 43.2% (16 cases) and 56. 8% (21 cases) respectively. The incidence of permanent and transient hypothyroidism were 16 (43.2%) and 21 (56, 8%), respectively. In permanent CH, 11 cases (%.68.2) had dyshormonogenesis and 5 cases (%.31.2) had thyroid dysgenesis. Significant statistical difference was only in family history of thyroid disease (34, 3% Positive family history in CH vs. 13.2% in control group, P-value 0.03). All other demographic characteristics and IQ had no statistical difference. Patients with CH diagnosed through neonatal screening and treated had normal growth as general population that indicates effective screening program and treatment in this area (3.2%). https://acta.tums.ac.ir/index.php/acta/article/view/4553 https://acta.tums.ac.ir/index.php/acta/article/download/4553/4643