Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 11 4 2025 04 18 529 532 Shideh Ariana Assistant Professor of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, School of Medicine, Preventative Gynecology Research Center, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Parnian Adhami Moghadam School of Medicine, Ilam University of Medical Sciences, Ilam, Iran. & Tehran Medical Sciences Islamic Azad University, Tehran, Iran. 2025 02 02 2025 02 15 Background: Gestational diabetes mellitus (GDM) causes various complications for the patient. Methods: This study included patients admitted to the women’s ICU. These patients were divided into a case and control group. Vitamin D was measured in all patients using the same laboratory kit and the results were categorized as Vit D insufficiency, Vit D deficiency and Vit D severe deficiency. Data This study was conducted using a registry checklist that included questions on Serum vitamin D levels, Anemia, Education, Age and Body mass index (kg/m2) which was completed using information available in the patient's clinical record. Results: Result showed, in the Case Group, the mean (SD) age was 28.96 (1.54), BMI was 24.6 (0.81), and 48% of the mothers had anemia. Also, in the control group, the mean (SD) age was 29.2 (1.22), BMI was 25.96 (1.69), and 28% of the mothers had anemia. also, the findings showed that in the Case Group, 56% of mothers had Vit D deficiency, 16% had Vit D insufficiency, and 28% had severe Vit D deficiency. Also, in the Control Group, 32% of mothers had Vit D deficiency, 56% had Vit D insufficiency, and 12% had severe Vit D deficiency. Also, different vitamin D percentages were reported in the two groups studied(p<0.05). Conclusion: Given the relationship between vitamin D and GDM, it is recommended that necessary preventive measures be taken in this regard to prevent pregnant mothers from contracting the disease. https://aacc.tums.ac.ir/index.php/aacc/article/view/1194