title: Prevalence of subclinical hypothyroidism in pregnant women in tehran-iran.
abstract: BACKGROUND
  Maternal subclinical hypothyroidism during pregnancy is associated with various adverse outcomes. Recent consensus guidelines advocate universal thyroid function screening during pregnancy. There are no data from Iran about the prevalence of thyroid hypofunction in pregnancy. This study aims to find the prevalence of thyroid dysfunction.
  
  
  METHODS
  In this descriptive cross sectional study, thyrotropin (TSH) was measured in 3158 pregnant women irrespective of gestational age from October 2008-March 2012. If TSH was more than 2.5 mIU/L in the first trimester or more than 3 mIU/L in the second or third trimester, free T4 was measured to diagnose subclinical/ overt hypothyroidism. If serum free T4 was in the normal range (0.7-1.8 ng/dl) the diagnosis was subclinical hypothyroidism and if below the normal range, overt hypothyroidism was diagnosed.
  
  
  RESULTS
  A total of 3158 pregnant women were evaluated. One hundred forty seven of them were diagnosed as hypothyroidism. Subclinical hypothyroidism and overt hypothyroidism were present in 131 (89.1%) and 16 (10.9%) women respectively. Prevalence of subclinical hypothyroidism was 4.15%. Most of the subclinical and overt hypothyroidism cases were diagnosed in the first trimester.
  
  
  CONCLUSIONS
  It appears logical to check TSH during pregnancy due to the observed prevalence of subclinical hypothyroidism.
authors.affiliation: Department of Obstetrics and Gynecology, Taleghani University Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Obstetrics and Gynecology, Shahid Beheshti University of Medical Sciences, Genomic Research Center, Infertility and Health Reseach Center, Tehran, Iran.
authors.forename: Fakhrolmolouk
authors.initials: F
authors.lastname: Yassaee
authors.affiliation: Department of Obstetrics and Gynecology, Taleghani University Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Obstetrics and Gynecology, Shahid Beheshti University of Medical Sciences, Genomic Research Center, Infertility and Health Reseach Center, Tehran, Iran.
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Farahani
authors.affiliation: Department of Community Medicine, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Abadi
keywords: Hypothyroidism; Pregnancy; Prevalence; Thyrotropin
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