en Nutrition Original Article Original Article <span style="font-size:14px;"><span style="font-family:times new roman;"><span style="color:#0000FF;"><strong><em>Background</em></strong><em>:</em></span> Gestational diabetes mellitus (GDM) is a common disorder in pregnancy. The association of trans fatty acids (TFA) intake and risk of GDM have been reported; It remains unclear whether dietary TFA can influence GDM risk. We examined the effect of low TFA dietary intakes during pregnancy on risk of GDM.<br> <span style="color:#0000FF;"><strong><em>Methods</em></strong><em>:</em></span> This randomized controlled trial was performed on 800 pregnant women who were randomly divided into 393 intervention and 407 comparison groups with gestational age <span dir="RTL">&ge;</span>7 weeks. In the intervention group, the diet of pregnant women was designed in such a way that their daily intake of TFA content was less than1% but in control group, the daily intake of TFA content was not changed. The dietary intake was assessed using a 24-hour dietary recall questionnaire for three non-consecutive days at the beginning of the pregnancy before week 7, and at 13, 25 and 35 weeks. Diagnosis of GDM was performed using a 3-hour glucose tolerance test with 100 g glucose at 24-28 weeks of gestation.<br> <span style="color:#0000FF;"><strong><em>Results</em></strong><em>:</em> </span>14 women in the intervention group (5%) and 31 women in the control group (8%) were diagnosed with GDM. Chi-square test did not show any significant difference between two groups (P=0.08). Cox model was used and the variables were examined in four multivariate models that none of the modals showed a statistically significant difference between the two groups regarding the incidence of GDM.<br> <span style="color:#0000FF;"><strong><em>Conclusion</em></strong><em>:</em> </span>It seems that the diet with low trans-fatty acid content has no effect on the incidence of GDM.</span></span> Gestational diabetes mellitus, Trans-fatty acids, 24-hour dietary recall 197 204 http://caspjim.com/browse.php?a_code=A-10-869-1&slc_lang=en&sid=1 Seideh-Hanieh Alamolhoda alamolhoda.h@gmail.com 100319475328460016826 100319475328460016826 No Midwifery and Reproductive Health Research Center, Department of Midwifery and Reproductive Health, school of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran Masoumeh Simbar msimbar@yahoo.com 100319475328460016827 100319475328460016827 No Midwifery and Reproductive Health Research Center, Department of Midwifery and Reproductive Health, school of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran Parvin Mirmiran parvin.mirmiran@gmail.com 100319475328460016828 100319475328460016828 No Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran parvaneh mirabi parvaneh_mirabi@yahoo.com 100319475328460016829 100319475328460016829 Yes Infertility and Reproductive Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran