Tehran University of Medical Sciences Journal of Family and Reproductive Health 1735-8949 2 2 2008 06 15 75 80 Ahia Garshasbi Department of Obstetrics and Gynecology, Faculty of Medicine, Shahed University, Tehran, I.R. Iran Soghrat Faghihzadeh Department of Biostatistics, Faculty of Medicine, Tarbiat Modarres University, Tehran, I.R. Iran Mohammad Mehdi Naghizadeh Department of Biostatistics, Faculty of Medicine, Tarbiat Modarres University, Tehran, I.R. Iran Mandana Ghavam Department of Midwifery, Faculty of Medicine, Tarbiat Modarres University, Tehran, I.R. Iran 2015 10 04 Objective: To evaluate the prevalence of gestational diabetes mellitus (GDM) and its risk factors in Tehran. Materials and Methods: From March 2002 to October 2004, screening for GDM was performed on 1804 women in Tehran. All pregnant women were referred for a 50 g oral glucose challenge test (OGCT) between 24th and 28th week of gestation. All subjects with an abnormal GCT (blood glucose level ≥130 mg/dl) underwent an oral glucose tolerance test (OGTT) within 1 week after the abnormal screening test. The prevalence of GDM was estimated. Results: The glucose challenge test was positive in 38.1% of cases .The prevalence of GDM for the whole cohort was 6.8%. About 78.6%   of our population were at medium or high risk for GDM and, therefore, would have been screened. The rate of GDM was significantly higher in women with a positive family history of diabetes, positive history of GDM, older age, multiparity, pre-pregnancy obesity, greater weight gain during pregnancy, history of infertility, chronic hypertension, history of stillbirth pregnancies and abortion. After logistic regression analysis, GDM diagnosis was significantly correlated with age (P<0.001), pre-pregnancy BMI (P=0.005), family history of diabetes (P<0.001), history of GDM (P=0. 002), chronic hypertension (P<0.001) and glucosuria during current pregnancy (P<0.001). Conclusion: In populations with medium/high risks for GDM (like the Iranian) universal screening is recommended to identify women with diabetes mellitus. https://jfrh.tums.ac.ir/index.php/jfrh/article/view/35 https://jfrh.tums.ac.ir/index.php/jfrh/article/download/35/35