Effect of Two Different Doses of Vitamin D Supplementation on Uterine Myoma on South East Iranian Population; A Clinical Trial

Objective: Uterine myoma is the most common benign tumor however with significant distress and reduced quality of life in affected women. Besides, vitamin D deficiency may be a risk factor for uterine myoma. This study aimed to evaluate the effect of vitamin D supplements on the size of myoma in women with vitamin D insufficiency or deficiency. Materials and methods: This clinical trial was conducted in a teaching hospital from 2019 to 2020. According to baseline vitamin D level, participants were assigned into two interventional equal groups (vitamin D deficiency or insufficiency) to receive either 1000 IU daily or 50000 IU weekly vitamin D for 12 weeks. The size and location of the uterine myoma were compared before and after the intervention. Results: Totally, 137 women with uterine myoma were enrolled. Based on baseline vitamin D level, 52 cases had vitamin D insufficiency and 85 cases had vitamin D deficiency. No significant difference was observed in age and BMI in both groups. The location of the subserosal and intramural myoma did not differ, otherwise, the percent of the submucosal myomas were increased significantly (p=0.020) after the intervention. In both groups decreased myoma size otherwise not significant was seen after the intervention (p=0.148 and p=0.664 respectively). Conclusion: Vitamin D supplementation may not be effective in women with vitamin D insufficiency or deficiency in the short term to reduce myoma size.