The Effect of Vitamin D Supplements on Reducing the Size of Uterine Leiomyoma in Women with Vitamin D Deficiency

Regarding the high prevalence of uterine leiomyoma and vitamin D deficiency, this study aimed to determine the effect of administration of vitamin D supplement on the amount of uterine leiomyoma in women with vitamin D deficiency. In a double-blind clinical trial, 70 patients with uterine leiomyoma and vitamin D deficiency were distributed in two equal groups, which received supplements of 50,000 unit of vitamin D every two weeks for 10 weeks and placebo, respectively. Serum level of vitamin D and size of uterine leiomyoma was measured in both groups before and 10 weeks after treatment, and compared between the two groups. Findings: 10 weeks after the intervention, serum level of vitamin D was 36.08 ± 11.15 and 16.25 ± 5.52 ng/dl in case and control groups, respectively, and the difference between the two groups was significant (P < 0.001). Moreover, 10 weeks after the intervention, the mean size of leiomyoma was 52.58 ± 14.4 and 61.11 ± 12.5 mm in case and control groups, respectively, and the difference between the two groups was significant (P = 0.006). The findings suggest that vitamin D intake decreases the amount of uterine leiomyoma, and therefore it seems that vitamin D is a good way to treat leiomyoma.