The effect of vitamin D supplementation on the size of uterine leiomyoma in women with vitamin D deficiency

Uterine leiomyomas (fibroids) are the most common benign pelvic tumors in women of reproductive age with an incidence ranging from 5.4% to 77%, Also, there is a high prevalence of vit D deficiency in Iran and there are the numbers of in vivo and vitro biological studies on the relationship of vitamin D and uterine leiomyomas. The aim of this study was to evaluate the effect of vit D supplementation on the size of uterine leiomyoma in women with vit D deficiency.

This double-blind prospective clinical trial was performed on 69 patients with uterine leiomyomas who had vit D deficiency. Group A (n=35) was treated with vit D 50,000 IU every 2 weeks for 10 weeks, while group B (n=34) received placebo with same color and shape. Finally, the leiomyoma size in both groups was compared (IRCT: 20160521027998N5).

After a 10-week intervention, 25-hydroxyvitamin D3 levels were significantly higher in group receiving vitamin D (36.08 vs 16.25 ng/ml). (P<0.001) Leiomyomas size in vit D group significantly decreased as compared to placebo group (52.58 vs 61.11 mm, respectively).

Our results showed that administration of vit D3 may reduce the size of leiomyoma. It seems that vitamin D administration is the effective way to treat leiomyoma.