The gut microbiome is the community of 100 trillion micro¬organisms including bacteria, archaea, yeast, helminth parasites, and viruses that inhabit our gut and a healthy community of microorganisms contributes to our overall health and well-being. The impact of the gut microbiome extends beyond the gastrointestinal and is involved in maintaining health status of other body sites including the female reproductive tract, which also has its own microbiome community. A bi-directional relationship exists between stress and the microbiome through the brain-gut-microbiome axis. Psychological stress significantly alters microbiome communities of the body and in turn the microbiome can interact directly and indirectly with the nervous system through metabolites and constituents.
Changes to levels of circulating gonadal hormones such as oestrogen can have adverse impacts on a range of physiological factors with clinical implications for brain cognition, gut health and female reproductive health. Oestrogen can influence the gut microbiome and vice versa where the gut microbiome influences host oestrogen levels through the secretion of β-glucuronidase, an enzyme which deconjugates oestrogen. This enables metabolised oestrogen to be reabsorbed by the gut and released into the bloodstream and travel to distal sites including the vaginal epithelium leading to physiological changes through downstream gene activation, epigenetic effects, triggering of signalling cascades as well as increasing Lactobacillus species.
Infertility is a global medical and social condition attributed to various pathophysiological alterations and is associated with stress, anxiety and depression with assisted reproductive technology also being shown to impact on psychological well-being.
Changes in the microbiome induced by stress can potentially influence oestrogen metabolising bacteria which significantly disrupts this homeostasis leading to altered levels of circulating oestrogens potentially influencing reproductive success.
Therefore, there is a need to address the role of the microbiome in the emotional and psychological aspects of infertility with the potential to highlight the interaction between nutrition, microbes and host response in the pre-conception period enabling new applications in the field of personalised nutrition & medicine for infertility.