The impact of vitamin D treatment on pregnancy rate among endometriosis patients: a systematic review and meta-analysis

Abstract

Background: Vitamin D supplementation is supposed to have an important role in the management of several endometriosis-related aspects, offering potential relief to affected individuals. Herein, the authors aim to evaluate the impact of vitamin D on pregnancy rates and clinical symptoms in women with endometriosis.

Methods: The authors extensively searched PubMed, Cochrane Library, EMBASE, Ovid MEDLINE, and CINAHL from their inception to 20 July 2023.

Results: Three randomized controlled trials involving 167 patients were included in this meta-analysis. The findings demonstrated that vitamin D supplementation exhibits efficacy in alleviating dysmenorrhea associated with endometriosis, as evidenced by a meta-analysis showing a significant reduction in dysmenorrhea (mean difference -1.41, 95% CI -2.61 to -0.22, P = 0.02). However, the impact on dyspareunia was inconclusive, with a non-significant mean difference of -0.2 (95% CI -1.62 to 1.22, P = 0.78). In contrast, dyschezia significantly decreased with vitamin D supplementation (mean difference -1.10, 95% CI -2.22 to 0.02, P = 0.05 However, the meta-analysis did not show a significant effect of vitamin D on chronic pelvic pain associated with endometriosis.

Conclusion: While antioxidant vitamin D supplementation demonstrates general effectiveness in alleviating endometriosis symptoms, such as dysmenorrhea, dyspareunia, and dyschezia, the existing literature lacks direct investigations into the specific impact of vitamin D on enhancing pregnancy rates among endometriosis patients. This observation prompts various hypotheses, suggesting that the positive effects of vitamin D supplementation on endometriosis-related symptoms may indirectly contribute to improved pregnancy outcomes and enhanced fertility.

Keywords: endometriosis; endometriosis-related symptoms; pregnancy rate; vitamin D.

Figure 1

Shows the metabolic pathway of vitamin D and targeted tissues. The images in the figure are adopted from smart.servier.com Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License. DBP, vitamin D binding protein; UVB, ultraviolet B rays.

Figure 2

PRISMA flowchart. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Figure 3

Geographic distribution of the countries of the included studies: both of Almassinokiani 2016 and Mehdizadehkashi 2021 in Iran while Nodler 2020 in USA.

Figure 4

Risk of bias graph: review authors’ judgements about each risk of bias item presented as percentages across all included studies.

Figure 5

Shows risk of bias summery.

Figure 6

(A) Forest plot of comparison: vitamin D vs. placebo, outcome: pelvic pain, (B) forest plot of comparison: 1 vitamin D vs. placebo, outcome: dyschezia, (C) forest plot of comparison: 1 vitamin D vs. placebo, outcome: dysmenorrhea, and (D) forest plot of comparison: 1 vitamin D vs placebo, outcome: dyspareunia.