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What Is the Menopausal Microbiome?
Now that you (hopefully) know a bit more menopause from a biological point of view (in case you missed it, see this link to the previous blog post), we can discuss the role the microbiome plays during perimenopause and into postmenopause. As a quick recap, menopause is essentially the final natural menstrual cycle that a woman experience, and takes place around age 50-55. The leadup to the final menstrual cycle is called perimenopause or the menopausal transition phase, and from one year after the final menstrual cycle, a woman is considered postmenopausal.
Most, if not all, of the symptoms experienced by women during perimenopause and postmenopause can essentially be explained by the loss of oestrogen, an important reproductive hormone. Both hormonal and non-hormonal treatments are available and can be used to help alleviate discomfort and manage these symptoms. Unfortunately, many women are unaware that treatment options even exist, while others believe that this discomfort is just a part of life they have to accept. Each experience is unique, and with the support of an experienced medical professional many women are able to improve their overall quality of life.
So where exactly does the microbiome fit into our understanding of menopause? Research into the menopausal microbiome has begun to gain traction in recent years, and this blog post will describe some of the important ideas around the menopausal microbiome.
The Vaginal Microbiome During the Reproductive Years
The community of microorganisms in the female reproductive tract — the vaginal microbiota — is highly dynamic and undergoes changes across an individual’s lifespan corresponding to the distinct phases of reproductive ageing. When it comes to the vaginal microbiome, there are several notable changes that occur during perimenopause and into postmenopause.
To understand these changes, it’s important to have a sense of what is going on during the reproductive stage, also known as ‘premenopause’ (not to be confused with perimenopause). During the reproductive stage, the vaginal microbiome of most women is dominated by various species of Lactobacillus. These important bacteria produce lactic acid which helps to maintain the ideal acidic pH of this environment. During this stage, the vaginal microbiota also has low overall diversity. When talking about microbiome composition, diversity is essentially a way of describing the variety of different microorganisms in a particular environment. High diversity means that there are lots of different unique microbes present, whereas low diversity means that there are fewer different microbes present (even if the total number of microorganisms is similar).
Glucose (i.e. sugar) is stored within the cells that line the vagina — the vaginal epithelium — as glycogen, and this storage is linked to the high levels of circulating oestrogen present during the reproductive stage. This glycogen (stored glucose) located in the vaginal epithelium serves as a key energy source for the bacteria within the vaginal microbiota, and contributes to the dominance of lactobacilli in this niche.
How Declining Oestrogen Changes the Vaginal Microbiome
During perimenopause, menopause, and postmenopause, circulating oestrogen levels decline dramatically, which contributes to changes in the vaginal epithelium. This in turn impacts glycogen storage and vaginal pH, causing a shift in microbial community composition — from being primarily dominated by Lactobacillus spp. (low diversity) to having increased diversity, with multiple different anaerobic bacteria present including Gardnerella, Prevotella, and Bacteroides among many others.
Why Increased Vaginal Diversity Is Not Always a Good Thing
Unlike other microbiomes in the body, increased diversity is not necessarily beneficial in the vagina, and in fact is usually associated with vaginal dryness and bacterial vaginosis in premenopausal women. Therefore, the increase in microbial diversity reported in postmenopausal women is unsurprisingly linked to heightened inflammatory responses and uncomfortable symptoms including discharge, odour, and elevated pH. In fact, the menopausal microbiome is linked to an increased susceptibility to urogenital discomfort and infections including vaginitis and bacterial vaginosis.
Hormonal Treatments and the Vaginal Microbiome
Menopausal Hormone Therapy (MHT) functions by replacing the lost oestrogen that occurs with natural reproductive ageing. This can be in the form of systemic hormone therapy, or a more targeted approach using low-dose vaginal oestrogens that are administered locally (as either creams or pessaries), which have been shown to reduce the vaginal pH. This suggests that this treatment can indirectly modify the vaginal microbiota composition. This explains why MHT can be so effective as a treatment — it can help restore a Lactobacillus-dominant vaginal microbiome by alleviating some of the changes to the vagina that underpin the symptoms of menopause.
Non-Hormonal Treatment Options: What the Evidence Says
When it comes to non-hormonal treatment options, including personal lubricants and moisturisers as well as natural therapies, although these are used fairly often, it is important to keep in mind that the long-term safety and efficacy of most of these interventions has not been definitively established. There is no complementary medicine that is as effective as oestrogen therapy for relieving menopause symptoms.
However, there is some evidence that certain interventions can potentially improve symptoms. One small study investigated whether taking sea buckthorn oil in capsule form could improve the integrity of the vaginal epithelium. This study found that participants given the sea buckthorn oil had some improvements in the integrity of the vaginal epithelium while those given the placebo did not. Further work is needed; however, this study does show that there may be some potential for non-hormonal therapies in alleviating symptoms.
The Future of Menopausal Microbiome Treatment: Precision Probiotics and Vaginal Microbiome Transplants
Looking beyond the treatment options that are currently available, an exciting potential strategy based on the growing understanding of the vaginal microbiome is the use of ‘precision probiotics’ that are specifically designed and tailored for each individual.
Vaginal Microbiome Transplant (VMT) is also being investigated for recurrent bacterial vaginosis and may eventually have applications for management of menopause in the future. At this stage, more evidence is required to expand the options currently available for women, as well as improved knowledge and education.
Conclusion
Overall, there is clearly a growing understanding of the role the vaginal microbiome plays throughout the various stages of reproductive ageing and particularly in perimenopause and postmenopause. As we begin to explore the clinical significance of the microbiome during perimenopause and postmenopause, this could enable new approaches to treatment and symptom management to be developed.
Sources:
https://doi.org/10.1038/s44294-024-00050-y
https://doi.org/10.3389/fendo.2025.1562332
https://doi.org/10.3390/diagnostics13061193