The Effect of Vitamin D Supplementation on Size of Uterine Leiomyoma in Women with Vitamin D Deficiency

Abstract

BACKGROUND: Uterine leiomyomas (fibroids) are the most common benign genital tumors in women. There is a high prevalence of vitamin D deficiency and uterine leiomyomas. AIM: To evaluate the effect of vitamin D supplementation on the size of uterine leiomyoma in women with vitamin D deficiency. MATERIALS AND METHODS: It is case–control prospective study which was done in Gynecology Ward at Basrah Maternity and Child Hospital from January 2020 to August 2022. Patients at ages 20–45 years were initially included in the study if they were diagnosed with 1–3 uterine fibroids with a mean diameter ≥10 mm. Serum vitamin D levels were estimated for all women before intervention and in those with deficiency of vitamin D (level <30 ng/mL). Patients with vitamin D deficiency were divided into 2 groups. The 1st group was women who received vitamin D 50,000 cholecalciferol (oral solution) IU weekly for 10 weeks followed by 2000 IU daily for 6–9 month (as study group), while 2nd group received placebo (control group). After the duration of treatment, vitamin D level was estimated and sonography was done to assess the fibroid size at 9–12 months later. In relation to the achievement of normal 25-OH-D3 levels, after the supplementation, the studied population were divided into 2 subgroup of patients: “gave response” and “non-responders” according to their response to treatment. RESULTS: Vitamin D level was 17.6 (±3.0) ng/mL and calcium status was 7 mg/dL among 43 females of the study group. Vitamin D level was 34.7 ± 5 ng/mL after 12 months vitamin treatment (p < 0.05). The early vitamin level among 23 control females was 22.4 ± 7.8 ng/mL in comparison to 24.6 ± 6.7 ng/mL after 12 months (p > 0.05). There was no change for calcium level before and after 12 months period (8.6 vs. 7.9 mg/dL respectively). No changes were noticed among both the study and the control groups as far as the type and position of leiomyoma between the 1st and the 2nd ultrasound after 12 months of therapy. CONCLUSION: Lower serum vitamin D levels are significantly associated with the occurrence of uterine fibroids.