Vitamin D Supplementation for Uterine Fibroids: What Does the Evidence Say? A Systematic Review of Primary and Secondary Outcomes

Abstract

Introduction: Uterine fibroids affect millions of women, and non-surgical management options are limited. Vitamin D, with its potential role in cell growth regulation, may be a promising non-surgical option.  

Objectives: This study reviews human studies from 2018 to 2023 to assess how vitamin D affects uterine fibroids (UFs). It aims to identify primary and secondary outcomes related to vitamin D's impact on UFs and stresses the importance of a core outcome set (COS) in fibroid research. 

Methods: A comprehensive search of PubMed, MEDLINE, Google Scholar, and the Cochrane Library used specific keywords related to vitamin D, uterine fibroids/myoma/leiomyoma, and primary and secondary outcomes. The literature search was limited to English-language publications and studies published before October 30, 2023. The review follows the PRISMA guidelines. Quality assessment was performed. 

Results: Eight relevant studies with a total of 565 participants were included. In all studies, the primary outcome focused on vitamin D's effect on the volume/size of UFs. The most reported secondary outcomes included changes in vitamin D levels, pelvic pain or pressure, fatigue and menstrual bleeding, quality of life, and fibroids. The results show that ​​vitamin D supplementation may have potential benefits for uterine fibroids, though the evidence remains inconclusive. While some high-quality studies reported reductions in fibroid size, others did not observe significant impacts. However, several studies have shown improvements in secondary outcomes, such as pain and quality of life.​​ 

​​Conclusion: ​The mixed results highlight the need for more rigorous, standardized research using a core outcome set (COS). Future well-designed RCTs are necessary to provide definitive answers on the effectiveness of vitamin D supplementation for managing UFs.​