fa پژوهشي اصیل Original Research <p><strong>Background and Objective:</strong> Thyroid function problems are often present with prematurity disorders. Thyroid<br> hormones regulate growth and distinguish body organs; especially they affect central nervous system and<br> metabolism of carbohydrates, lipids, and vitamins. Thus, these hormones should be evaluated. The present study<br> aims to determine the mean level of thyroid hormones among premature infants referred to NICUs of Aliasghar<br> and Akbarabadi hospitals in 5th day, 2nd and 4th weeks.<br> <strong>Methods: </strong>In this cross-sectional study 140 infants who referred to Aliasghar and Akbarabadi hospitals NICU<br> since May 2012 were examined after obtaining written consent from their proxies. At the 5th day 1cc blood sample<br> was taken; and the procedure was repeated at the 2nd and 4th weeks. TSH and T4 were measured and the<br> mean was calculated for the 3 stages.<br> Findings: A total of 140 patients (80 boys) were evaluated. Gestational mean age was 31.91 weeks. At the<br> 5th day the means of TSH and T4 were 4.16 and 8.71, at the 2nd week 4.47 and 8.12, and for the 4th week 4.08<br> and 8.76, respectively.<br> <strong>Conclusion: </strong>In current study TSH level at the 5th day was 4.16&plusmn;3.3 and T3 serum level 8.71&plusmn;3.4. TSH in 2nd<br> week measuring was 4.47&plusmn;2.5 and T4 was 5.12&plusmn;2.9. At the 4th week the TSH level was 4.08&plusmn;1.9 and T4 was<br> 8.76&plusmn;2.8. TSH level was independent from gestational age, but T4 serum level had direct association with gestational<br> age. There was no relationship between thyroid hormones&rsquo; level with birth weight, thyroid disorders history<br> in infants&rsquo; family, and consuming thyroid medications during pregnancy.</p> Thyroid hormone, TSH, T3, T4, Gestational age, Prematurity, Akbarabady hospital, Aliasghar hospital 1 4 http://ijca.iums.ac.ir/browse.php?a_code=A-10-38-2&slc_lang=fa&sid=1 Nasrin Khalesi nasrinkhalesi1394@gmail.com 1003194753284600353 1003194753284600353 Yes Iran University of Medical Sciences, Tehran, Iran Maryam Sabouteh 1003194753284600354 1003194753284600354 No Iran University of Medical Sciences, Tehran, Iran