en Preventive Medicine & Community Health Preventive Medicine & Community Health Original Research Original Research <strong>Background: </strong>The clinical suspicion of Congenital Hypothyroidism (CH) is identified by abnormal results in the first test of Thyroid Stimulating Hormone (TSH) (5-9.9 mIU/L), and normal results in re-test (TSH<4 mIU/L). The CH has a contribution to physical and mental health. This study aimed to determine the Intelligence Quotient (IQ) score in children with suspected congenital hypothyroidism.<br> &nbsp;&nbsp; <strong>Methods:</strong>&nbsp; This research is a retrospective cohort study conducted in Mashhad, Iran. The IQ scores of 1976 children at the age of 6 were considered as an outcome variable. The history of CH screening for each newborn was assessed, then all suspected CH newborns that diagnosed healthy in re-test were considered as an exposed group, the effects of this situation on IQ score was assessed using logistic regression. All analysis was performed in STATA.<br> &nbsp;&nbsp; <strong>Results:</strong> The averages of IQ score (p<0.001), weight (p=0.024), and height (p<0.001) in the exposed group were lower than the unexposed group. The exposed group was related to those whose parental education was less or equal to 12 years (p<0.001). Similarly, the history of CH and maternal education for &le;12 years were detected as risk factors for having an IQ score of <90 in children.<br> &nbsp;&nbsp; <strong>Conclusion:</strong> Aside from the link between parental education and clinical suspicion of CH in neonates, our findings underline the possible strong effect of CH status and maternal education for &le;12 years on reducing IQ scores in the next years of child life. Intelligence quotient, Suspected CH newborn, Congenital hypothyroidism 797 801 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-4807-1&slc_lang=en&sid=1 Shahin Saeidinejat saeedish1@mums.ac.ir 200319475328460064348 200319475328460064348 Yes 1. Department of Persian Medicine, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Nosrat Ghaemi Belhouri 200319475328460064349 200319475328460064349 No 2. Department of Pediatric Endocrinology and Metabolism, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Fahimhe Attarian attarian581@gmail.com 200319475328460064350 200319475328460064350 No Student Research Committee, Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran