Background: Fluctuations in endogenous hormones estrogen and progesterone during the menstrual cycle may offer vasoprotection for endothelial and smooth muscle (VSM) function. While numerous studies have been published, the results are conflicting, leaving our understanding of the impact of the menstrual cycle on vascular function unclear. The purpose of this systematic review and meta-analysis was to consolidate available research exploring the role of the menstrual cycle on peripheral vascular function. Methods: A systematic search of MEDLINE, Web of Science, and EMBASE was performed for articles evaluating peripheral endothelial and VSM function across the natural menstrual cycle: early follicular (EF) phase versus late follicular (LF), early luteal, mid luteal, or late luteal. A meta-analysis examined the effect of the menstrual cycle on the standardized mean difference (SMD) of the outcome measures. Results: Analysis from 30 studies (n=1,363 women) observed a "very low" certainty of evidence that endothelial function increased in the LF phase (SMD:0.45,p=0.0001), with differences observed in the macrovasculature but not the microvasculature (SMD:0.57,p=0.0003, I²=84%; SMD:0.21,p=0.17,I²=34% respectively). However, these results are partially explained by differences in FMD [ex. discrete (SMD: 0.86, p=0.001) versus continuous peak diameter assessment (SMD: 0.25, p = 0.30)] and/or menstrual cycle phase methodologies. There was a "very low" certainty that endothelial function was largely unchanged in the luteal phases, and VSM was unchanged across the cycle. Conclusions: The menstrual cycle appears to have a small effect on macrovascular endothelial function, but not microvascular or VSM function; however, these results can be partially attributed to methodological differences.

中文翻译：

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月经周期对绝经前女性外周血管功能的影响：系统评价和荟萃分析。

背景：月经周期期间内源性激素雌激素和孕激素的波动可能为内皮和平滑肌（VSM）功能提供血管保护。尽管已经发表了大量研究，但结果相互矛盾，使得我们对月经周期对血管功能影响的理解尚不清楚。本系统综述和荟萃分析的目的是巩固现有研究，探索月经周期对外周血管功能的作用。方法：对 MEDLINE、Web of Science 和 EMBASE 进行系统检索，查找评估自然月经周期中外周内皮和 VSM 功能的文章：卵泡早期 (EF) 阶段与卵泡晚期 (LF)、黄体早期、黄体中期或黄体中期。黄体晚期。一项荟萃分析检查了月经周期对结果测量的标准化平均差 (SMD) 的影响。结果：对 30 项研究（n=1,363 名女性）的分析发现，证据质量“非常低”，表明 LF 期内皮功能增强（SMD：0.45，p=0.0001），在大血管系统中观察到差异，但在微血管系统中没有观察到差异（ SMD：0.57，p=0.0003，I ² =84%；SMD：0.21，p=0.17，I ² =34%。然而，这些结果部分是由 FMD 的差异来解释的。离散（SMD：0.86，p = 0.001）与连续峰直径评估（SMD：0.25，p = 0.30）]和/或月经周期阶段方法。内皮功能在黄体期基本没有变化，并且 VSM 在整个周期中没有变化，这一点的确定性“非常低”。结论：月经周期似乎对大血管内皮功能影响较小，但对微血管或 VSM 功能影响不大；然而，这些结果可部分归因于方法上的差异。