A research group at Okayama University has discovered a common disruption of the microbiome in three areas—the vagina, urinary tract, and intestines—in menopausal-related genitourinary syndrome (GSM).
GSM, which is estimated to affect 50-70% of postmenopausal women, causes vaginal dryness and pain, urinary problems, and other symptoms that significantly impair quality of life (QOL). The standard treatment is local estrogen administration to the vagina, but there are cases where this cannot be used or is insufficiently effective, such as in women with a history of breast cancer.
In response to this situation, this research group focused on the disruption of the microbiome. By analyzing 23 studies (totaling 5,027 participants) reported in 12 countries worldwide from 2016 to 2025, they comprehensively examined changes in the microbiome of three sites: the vagina, urinary tract, and intestines.
As a result, a common disruption was consistently observed in all three sites after menopause: a decrease in beneficial bacteria, Lactobacillus, and an increase in bacterial diversity. The changes common to all three sites suggested the existence of a new concept called the "vaginal-bladder-gut axis," in which the vagina, bladder, and intestines mutually influence each other.
Furthermore, it was found that estrogen supplementation partially restores the dominance of lactobacilli, but this does not necessarily correlate with symptom improvement. This suggests that GSM is not simply a problem of estrogen deficiency associated with menopause, but that a systemic disruption of the bacterial flora spanning the vagina, bladder, and intestines may be involved.
This study presents a framework for re-examining GSM from the perspective of the microbiome and the "vagina-bladder-intestinal axis." This finding has the potential to lead to new treatment methods for cases that are difficult to treat with conventional therapies, and to the realization of personalized medicine. In the future, promoting simultaneous longitudinal follow-up studies of the vagina, bladder, and intestines in the same case will contribute to the establishment of groundbreaking prevention and treatment methods for GSM.
Paper information: [Maturitas] Gut, Vaginal, and Urinary Microbiome Alterations in Women with Genitourinary Syndrome of Menopause: A Systematic Review
