Overview

• Researchers tracked 220 women under age 35 across 44 Chinese cities, comparing 110 PCOS patients with 110 matched controls.
• Women with PCOS carried about half the normal levels of the gut bacterium Parabacteroides merdae, a deficit linked to nearly double the risk of miscarriage, preterm birth, gestational diabetes and low birth weight.
• Metabolomic profiling showed PCOS participants had 39% higher isoleucine and 10% lower short-chain fatty acids in blood, with laboratory tests indicating these shifts drive premature senescence in endometrial cells.
• The study abstract is slated for publication in Human Reproduction and investigators are moving ahead with trials of microbiome-modulating therapies, including probiotics and dietary adjustments.
• Some experts question whether accelerated endometrial aging truly underlies PCOS pregnancy risks, noting that reproductive function often improves later in life.