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The impact of estrogen status on the gut microbiome: a systematic review and meta-analysis

K. Saravinovska, D. Santi, F. Costantino, A. Prete, A. Šojat, G. Spaggiari, M. Ivović, I. Lambrinoudaki et al.

Frontiers in Endocrinology, 2026

1,222 participants · 5 citations

Abstract

Background Estrogens have been proposed as modulators of gut microbiome (GM) composition, yet evidence from observational studies remains inconsistent. Objective This meta-analysis aimed to systematically summarise existing evidence on GM alterations in hypoestrogenic women – post-menopausal or premature ovarian insufficiency (POI) – compared to euestrogenic pre-menopausal controls. Methods PubMed, SCOPUS and Embase were searched through December 2024 for studies comparing GM characteristics between hypoestrogenic and pre-menopausal women. Primary outcome was α-diversity (Shannon index). Secondary outcomes included relative abundances of Bacteroidetes, Firmicutes, and the Bacteroidetes to Firmicutes ratio. Random-effects models were used for data synthesis. Results Out of 1092 studies screened, 7 met the inclusion criteria (n = 45 women with POI, n = 1222 post-menopausal women, n = 463 eustrogenic controls). No significant differences were observed in α–diversity (p=0.990), Bacteroidetes (p=0.440), or Firmicutes abundance (p=0.110) between hypoestrogenic and euestrogenic groups, irrespective of POI or postmenopause. Similarly, the Bacteroidetes to Firmicutes ratio showed no significant difference between the groups (p=0.400). Study heterogeneity was high (I² 61-99%). Conclusion Current evidence does not support consistent differences in GM diversity or major bacterial phyla between hypoestrogenic and euestrogenic women. Given the substantial heterogeneity, limited control of…

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Evidence Hub reads this as a meta-analysis. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 1,222 participants or records.

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