Does Vitamin D Supplementation Affect Postpartum Anthropometric Measurements in Gestational Diabetes? A Randomized Controlled Clinical Trial

Introduction: We know mothers with gestational diabetes mellitus (GDM) are in the higher postpartum risk of spare weight gain and type 2 diabetes. Excessive postpartum weight gains also lead to low maternal vitamin D levels. So, we decided to evaluate the result of a single mega dose of injectable vitamin D in postpartum weight gain and other anthropometric measurements in the new cases of GDM. Methods: This is a randomized clinical trial study with the followup time of 3 months. Totally 45 people were randomly allocated into control and intervention groups. The intervention group got only one IM injection of 300,000 IU of vitamin D whereas controls did not. The body mass index (BMI), waist circumference, hip circumference and waist to hip ratio were quantitated. Results: 24 mothers with an average age of 30.7±6.2 in the intervention group and 21 mothers with an average age of 29.5±4.0 in the control group took part in the study. Waist circumference and hip circumference reduced in the intervention group in compared to the control group (P value= 0.006), significantly. Changes of BMI were not significant after intervention (P value= 0.9). Conclusions: Only one single 300,000 IU dose of vitamin D decreased waist and hip circumference in postpartum of GDM women, but it did not find any significant effect on BMI. Further prospective studies with longer follow up period are necessary.