How Dysbiosis Disrupts Hormonal Health, Ovulation, and Egg Quality From the Inside Out — section

The disruption does not stop there. Dysbiosis also reduces production of short-chain fatty acids, particularly butyrate. This introduces a second mechanistic hit. Butyrate functions not only as a metabolic substrate for colonocytes but also as a histone deacetylase (HDAC) inhibitor involved in epigenetic regulation. Reduced butyrate availability alters chromatin accessibility and contributes to downregulation of estrogen receptor expression within endometrial tissue. The uterus becomes less responsive to estrogen signaling even if estrogen is present.