ABSTRACT
The aim of this study was to assess the geographical distribution of Congenital Hypothyroidism [CH] in Iran using Geographic Information System. The incidence of Congenital Hypothyroidism in each city and province calculated based on national CH screening program and then the map of its distribution was depicted. The spatial distribution of CH was assessed in each city by employing binominal test and Hotspot Analysis. The map of distribution of CH was drawn by ArcGIS version 9.2 software. The national incidence of CH [including both transient and permanent types] has been estimated 2.2/1000 in screened new borne babies. The distribution of CH seems more or less equally around the country and its spatial variation was not statistically significant. We did not find any specific CH Hot Spot in Iran. We did not find any particular explanation for high incidence of CH is Iran geographically; therefore other explanations for such a high risk in screened neonates should be investigated including the non-environmental factors and factors related to quality of screening program in Iran