Beyond the Gut: How Digestion Impacts Fertility
How does digestion affect fertility? Continue reading to find out how gut health, bowel regularity and nutrient absorption influence hormone balance and reproductive health - and what you can do to support both your gut and fertility naturally.
When we think of digestion we often think it’s what happens after a meal - but the gut does far more than process food, it plays a vital role in hormone regulation, nutrient absorption and your fertility.
If your gut is out of balance, your reproductive health might be too. Here’s how digestive health influences fertility, what signs to look out for and practical steps to improve both.
The Gut–Hormone Connection
Your gut and hormones are deeply connected. Inside your digestive tract lives a vast ecosystem of bacteria known as the gut microbiome - and a specific group called the estrobolome helps process and eliminate oestrogen.
When bowel movements slow down (for example, constipation), oestrogen can be reabsorbed rather than cleared from the body. This may lead to an imbalance between oestrogen and progesterone, contributing to irregular cycles, PMS, bloating or difficulties ovulating and conceiving.
But, on the other hand, loose stools or ongoing digestive upset can disrupt bile recycling and nutrient absorption, impacting your body’s ability to make and regulate hormones effectively. In both cases, hormone balance - and therefore fertility - can be affected.
Your gut also has an impact on your thyroid hormones too, and thyroid function is key for fertility. A healthy gut supports the conversion of inactive thyroid hormone (T4) into its active form (T3), but gut inflammation, gut dysbiosis and poor nutrient absorption can impair this process. Since thyroid hormones help regulate ovulation, your menstrual cycle and overall reproductive function, maintaining gut health indirectly supports thyroid balance and fertility.
Bowel Regularity and Detoxification
Our digestive and reproductives tracts are completely different so why would we think they are connected? But constipation and fertility are more connected than most people realise.
Regular bowel movements are one of the body’s main detoxification routes. When things slow down, hormones and toxins linger longer than they should, promoting inflammation and imbalance.
Meanwhile, chronic diarrhoea or loose stools may mean nutrients aren’t being absorbed properly, depriving your body of essential building blocks for egg and hormone production.
Ideally, aim for at least one comfortable, well-formed bowel movement daily. Anything less (or much more, particularly if they are very loose) could indicate that your digestion needs support.
Nutrient Absorption and Fertility
Even a healthy diet can fall short if your body isn’t absorbing nutrients efficiently. Gut inflammation, food sensitivities or enzyme imbalances can reduce absorption of key fertility nutrients such as:
Iron – supports oxygen delivery and egg development
Zinc – essential for egg and sperm quality
Magnesium – helps balance hormones and ease stress
B vitamins (especially B12 and folate) – support ovulation and implantation
Vitamin D – vital for hormone regulation and reproductive function
Deficiencies in these nutrients can have a direct effect on fertility potential for both men and women.
Inflammation and the Gut–Immune Axis
When the gut lining becomes compromised (sometimes referred to as “leaky gut”), food particles, bacteria and toxins can pass into the bloodstream, triggering immune reactions and inflammation. Have you ever had to rush to the toilet after eating a specific food (and I’m not talking about food poisoning), this could be “leaky gut” in action – and not an intolerance or sensitivity that you may think.
Chronic inflammation is linked to conditions including PCOS, endometriosis and thyroid dysfunction. Supporting the gut barrier through anti-inflammatory foods and lifestyle changes can help lower inflammation and improve reproductive outcomes.
How to Support Your Gut for Better Fertility
Healthy digestion starts with small, consistent habits. Try these evidence-based steps to optimise your gut health and fertility:
Eat slowly and chew thoroughly – proper chewing helps enzyme activity and nutrient absorption.
Stay hydrated – water keeps the digestive system moving and supports detoxification. Aim for 2 litres of water per day as a general rule of thumb.
Eat plenty of fibre – from vegetables, fruits, wholegrains, beans, lentils and seeds to feed that all important beneficial gut bacteria. Staying hydrated with an increase in fibre is essential.
Add probiotic and prebiotic foods – such as Greek yogurt, kefir, sauerkraut, kimchi, garlic and onions.
Bone broth – as well as being full of nutrients, bone broth is extremely gut healing.
Manage stress – high cortisol affects both digestion and ovulation. High cortisol = lowered progesterone.
Get personalised guidance if symptoms like bloating, constipation or loose stools persist - there may be deeper imbalances to address.
Your Gut: The Foundation of Fertility
Good digestion is about much more than comfort - it’s about creating the best internal environment for your hormones, eggs and sperm to thrive.
When your gut works well, nutrients are absorbed efficiently, inflammation is reduced and hormones stay balanced. These are the building blocks of a healthy menstrual cycle, improved egg quality, balanced hormones and stronger fertility outcomes.
If you’re experiencing digestive symptoms or preparing for conception, it may be time to explore your gut health as part of your fertility journey. I offer assessments and personalised nutrition plans to help you identify and correct any imbalances.
Any questions or you would like to discuss this further? Please don’t hesitate to get in touch, with the right advice we can get your digestion back on track, balance your hormones and support your fertility.
References
Baker, J. M., Al-Nakkash, L., & Herbst-Kralovetz, M. M. (2017). Estrogen-gut microbiome axis: Physiological and clinical implications. Maturitas, 103(103), 45–53. https://doi.org/10.1016/j.maturitas.2017.06.025
Fröhlich, E., & Wahl, R. (2019). Microbiota and Thyroid Interaction in Health and Disease. Trends in Endocrinology & Metabolism, 30(8), 479–490. https://doi.org/10.1016/j.tem.2019.05.008
Qi, X., Yun, C., Pang, Y., & Qiao, J. (2021). The impact of the gut microbiota on the reproductive and metabolic endocrine system. Gut Microbes, 13(1), 1894070. https://doi.org/10.1080/19490976.2021.1894070
Shin, J.-H., Park, Y.-H., Sim, M., Kim, S.-A., Joung, H., & Shin, D.-M. (2019). Serum level of sex steroid hormone is associated with diversity and profiles of human gut microbiome. Research in Microbiology, 170(4-5), 192–201. https://doi.org/10.1016/j.resmic.2019.03.003