​Gut Microbiome and Fertility: How Your Gut Health Impacts Conception and IVF Success

When it comes to conception and IVF outcomes, conversations usually revolve around egg quality, sperm health, hormone levels, and uterine receptivity. But increasingly, science is pointing to another key player in reproductive success: the gut microbiome.

This community of trillions of microbes in your gut doesn’t just affect digestion - it influences hormones, immunity, metabolism, and even how well your body responds to fertility treatments.
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If you’re trying to conceive naturally or through IVF, here’s why nurturing your gut may be one of the most powerful steps you can take.

The Gut–Hormone Connection

Your gut microbiome is a key regulator of hormonal balance - not just sex hormones like oestrogen and androgens, but also appetite hormones and even brain chemicals that shape mood and stress responses. All of these influence conception and IVF outcomes.

Oestrogen Metabolism: A specialised group of microbes, the estrobolome, produces enzymes that recycle oestrogen.

• Too much recycling → excess oestrogen, fuelling endometriosis, fibroids, and disrupted implantation.
• Too little recycling → inadequate oestrogen signalling, leaving the uterine lining underprepared for embryo attachment.

Androgens in PCOS: Individuals with PCOS often show microbiome disruption that is linked to insulin resistance, inflammation, excess androgens and anxiety. Restoring gut balance has been shown to lower circulating androgens and improve ovulatory cycles.

Appetite Hormones and Metabolic Health: The gut microbiome influences leptin and ghrelin, the hormones that regulate appetite and energy balance. Dysbiosis is linked with leptin resistance and disrupted hunger cues. High leptin concentrations may reduce the ovaries responsiveness to gonadotropins and have been shown to have a negative impact on IVF outcome.

Mood and Neurotransmitters: Through the gut–brain axis, microbes also shape mood by producing neurotransmitters like serotonin, dopamine, and GABA. Dysbiosis is linked with higher anxiety, depression, and altered stress responses.

For couples navigating fertility treatment, supporting the gut may help buffer the emotional toll of IVF and improve resilience.
 
Takeaway: A balanced gut equals balanced hormones - a foundation for conception and IVF success.

Inflammation, Implantation & IVF Outcome

Inflammation is an essential process in the body and it is necessary for ovulation and implantation. When inflammation is chronic though it damages eggs, sperm, and the endometrium.  We have spent a lot of time researching the processes of inflammation and oxidative stress and we love translating this knowledge into practice!

•Microbiome imbalances disrupt the protective intestinal barrier and allow bacterial fragments and toxins (like LPS) into the bloodstream, triggering chronic low-grade inflammation.

•High levels of systemic inflammation impact egg and sperm quality, and uterine receptivity. Increased inflammatory compounds are associated with lower fertilisation rates, poorer embryo quality, and reduced implantation success.

•A healthy gut microbiome is one of the body’s strongest regulators of the immune system. Beneficial microbes strengthen the gut barrier, train immune cells to respond appropriately, and produce short-chain fatty acids like butyrate, which calm inflammation.

Takeaway: By supporting gut diversity through diet and lifestyle, you can help keep inflammation under control supporting egg and sperm health, and creating a more receptive environment for conception and ongoing pregnancy.

Nutrient Absorption for Egg and Sperm Quality

Healthy eggs and sperm depend on nutrients like folate, vitamin D, zinc, iron, and omega-3s. Your microbiome plays a role in how well you absorb and activate them.

•Folate & B vitamins: Gut bacteria produce folate and influence methylation pathways critical for DNA integrity in eggs and sperm.

•Antioxidants: Microbes activate plant polyphenols (like those in berries and green tea), providing extra antioxidant protection against oxidative stress - a key driver of poor egg and sperm quality.

•Iron & zinc: Microbiome diversity improves mineral absorption, supporting ovulation and sperm motility.

Takeaway: A diverse gut ensures the nutrients you eat are bioavailable when your reproductive cells need them most.

Practical Ways to Nurture Your Gut Before IVF

1.Eat for diversity: Aim for 30+ plant foods per week - vegetables, legumes, nuts, seeds, herbs, and wholegrains. Each one feeds different microbes.

2.Prioritise prebiotics: Specialised fibres (like those found in Microbiome Essentials and Cacao Latte) directly fuel beneficial bacteria that make fertility-supporting compounds like butyrate.

3.Consider probiotics: Fermented foods (kefir, sauerkraut, miso) and clinically studied probiotic strains may rebalance the vaginal and gut microbiota. Probiotic supplements differ greatly in quality and efficacy, so it’s best to seek advice from an Accredited Dietitian before starting.

4.Balance protein: Include plant proteins (beans, lentils, quinoa, tofu) alongside lean animal sources to reduce inflammation and improve gut barrier function.

5.Limit endocrine disruptors: A healthy gut microbiome can reduce BPA and phthalate absorption, but lowering exposure (plastic bottles, food packaging) is equally key.

6.Lifestyle factors: Exercise, sleep, and stress management directly influence gut microbial composition and diversity.

Your Microbiome Matters

Your gut microbiome is more than a digestion aid - it is a fertility ally. By shaping hormone balance, reducing inflammation, enhancing nutrient absorption, and improving implantation, your gut microbes may hold the missing link to conception and IVF success.

If you’re preparing for IVF or trying to conceive, investing in your gut health could be the difference between another cycle and your long-awaited positive result.
 
Want Personalised Support?
If you’re preparing for conception or IVF, book a FREE 15-minute call with our team to discover how we can help optimise your gut for pregnancy success. You can also join us now in our Gut Health for IVF & Pregnancy Success to start today.
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Investing in nurturing your gut microbiome is investing in your fertility.

 
References
Bailey & Ayling, Sci Rep, 2018
Evans-Hoeker, et al., Fertil Steril, 2013.
Clark et al, 1995 Human Reprod
Cryan et al. (2019) Nat Rev Neurosci
Duval et al 2015 Fertil Steril
Gaskins et al. (2016) Hum Reprod
Liu et al. (2021) Front Immunol
Liu et al. (2022) Environ Int
Mena et al, 2019 Human Repro Update
Vulevic et al. (2015) Br J Nutr
Zheng et al. (2021) Cell Host Microbe