August 18, 2026
Emerging research suggests the gut microbiome may be linked to fertility through its effects on hormones, inflammation, and the uterine environment, though the evidence is still developing and mostly observational [1][2]. Researchers call this a "gut-reproductive axis," an active area of study rather than settled science.
Research points to a plausible connection rather than a proven one. A 2025 review describes a "gut-endometrial axis," where gut microbial metabolites appear to influence immune tolerance and the uterine lining, with dysbiosis linked to conditions like endometriosis, PCOS, and implantation difficulties [1]. Another review frames this as a "gut microbiota-gonadal axis," a two-way relationship between gut bacteria and reproductive hormones [2]. Both reviews are clear that most current evidence is correlational, meaning it shows a pattern rather than proving the gut causes fertility outcomes.
Gut bacteria can influence hormone metabolism and signalling, leading researchers to explore the microbiome as a regulator of hormonal processes relevant to reproduction, including how the body processes oestrogen [1][2]. This process, sometimes called the estrobolome, may be relevant to circulating hormone levels involved in ovulation and the menstrual cycle. Because this research is still relatively new, the practical size of this effect for any individual is not yet well quantified.
Yes, and research suggests it may matter more directly for fertility than the gut microbiome does. Reviews note that vaginal microbiome disruption is linked to conditions like preterm birth and difficulties with implantation during fertility treatment. Research suggests that the vaginal microbiome may be relevant to implantation and reproductive health more broadly [2][3]. The gut and vaginal microbiomes are related but distinct systems, part of the same broader picture of a healthy gut microbiome, and most fertility-specific microbiome research to date has focused more heavily on the vaginal environment.
General gut-supportive habits, such as eating a varied, fibre-rich diet, staying active, and getting adequate sleep, can support overall health alongside appropriate fertility care, but they are not a substitute for fertility care from a GP or fertility specialist. Our gut health quiz is a reasonable starting point if you want a general sense of your own gut wellness. If gut symptoms like bloating, irregular bowel habits, or pain are present alongside fertility concerns, mentioning both to a doctor may help build a fuller picture, since conditions like endometriosis and PCOS involve both systems.
| Linked in research | Not yet proven |
|---|---|
| Gut dysbiosis is associated with PCOS and endometriosis, both linked to fertility difficulty | That changing gut bacteria improves fertility outcomes directly |
| Gut bacteria appear to influence oestrogen metabolism | How much this specifically affects an individual's chance of conceiving |
| Vaginal microbiome stability is linked to implantation success | Whether gut-focused interventions meaningfully change IVF outcomes |
Can improving gut health increase fertility?
There is no established evidence that gut health changes alone increase fertility. The research shows associations between gut bacteria and reproductive conditions, but proven, direct interventions have not been established. Fertility concerns should be discussed with a GP or fertility specialist.
Are gut health and vaginal health connected?
They are related but distinct microbial communities. Research suggests both may play a role in reproductive health, with the vaginal microbiome having a more directly studied link to conditions like preterm birth and implantation.
If you are trying to conceive, general gut-supportive habits are reasonable to maintain alongside, not instead of, fertility care. Mention any persistent gut symptoms to your fertility specialist or GP, since conditions linked to both fertility and gut health, like PCOS and endometriosis, are worth investigating together.
This content is for informational purposes only and does not constitute medical advice. If you have concerns about your digestive health, please speak to a healthcare professional.
