Influence of phytoestrogens on endometrial thickness: a systematic review and meta-analysis

Abstract

The objective of this systematic review was to evaluate the influence of the use of phytoestrogens on variations in endometrial thickness in postmenopausal women. Randomized controlled trials were searched in the following electronic databases until March 2020: MEDLINE, Embase, Cochrane Library, Web of Science and LILACS. We used the terms ‘phytoestrogens’ and ‘endometrium’ or ‘endometrial hyperplasia’ to search for relevant trials. The data were analyzed using RevMan 5.3 software. A total of 10 studies involving 1476 patients were included. The difference in endometrial thickness was evaluated in 10 studies, with a total of 805 participants in the phytoestrogen group and 761 in the control group. Such a difference was not significant between groups after 3 months (standardized mean difference [SMD] 0.00, 95% confidence interval [CI] − 0.37 to 0.37; I² = 63%), 6 months (SMD −0.30, 95% CI −0.79 to 0.19; I² = 70%), 12 months (SMD −0.02, 95% CI 0.22 to −0.18; I² = 0%) and 24 months (SMD –0.09, 95% CI −0.25, 0.08; I² = 0%) of use. Our meta-analysis shows no changes in endometrial thickness in women using phytoestrogens. Evidence is still uncertain owing to the presence of heterogeneity among the studies currently available, whose reported outcomes cover a period between 3 and 6 months.

植物雌激素对子宫内膜厚度的影响:系统综述和荟萃分析 摘要

本系统综述的目的是评价应用植物雌激素对绝经后女性子宫内膜厚度变化的影响。截至2020年3月, 在电子数据库MEDLINE、Embase、Cochrane Library、Web of Science和LILACS中搜索随机对照试验。我们应用术语“植物雌激素”和“子宫内膜”或“子宫内膜增生”来搜索相关的研究。采用RevMan 5.3软件对数据进行分析。共纳入10项研究, 涉及1476例患者。10项研究评估了子宫内膜厚度的差异, 植物雌激素组共有805名参与者, 对照组有761名。3个月后组间差异无统计学意义(标准化均数差[SMD] 0.00, 95%置信区间[CI] 0.37 ∼ 0.37; I2=63%), 6个月(SMD 0.30, 95% CI 0.79 ∼ 0.19; I2=70%), 12个月(SMD 0.02, 95% CI 0.22∼0.18; I2=0%)和24个月(SMD -0.09, 95% CI 0.25∼ 0.08; I2 = 0%)。我们的荟萃分析显示, 应用植物雌激素的女性子宫内膜厚度没有变化。由于现有研究存在异质性, 证据仍不确定, 其报告的结果涵盖3 - 6个月的时间。

Keywords:

• Phytoestrogens
• endometrium
• menopause
• endometrial
• endometria
• hyperplasia
• systematic review

Potential conflict of interest

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Funding

The authors received no financial support for the research, authorship and/or publication of this article. This study was supported in part by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Brazil). MIR is recipiente of CNPq (Brazil) Productivity Fellowships. Also, this study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) [Finance Code 001].