PCOS, Fertility and Nutrition

‍Article by Maria Kolotourou, Dietitian-Nutritionist, BSc (Hons), MSc, RD

Polycystic ovary syndrome (PCOS) affects at least 1 in 10 women of reproductive age and is one of the most common causes of anovulatory infertility. For many women, receiving a PCOS diagnosis alongside fertility challenges can feel very overwhelming.

Nutrition plays a meaningful role in supporting fertility with PCOS; not as a replacement of medical treatment, but as a powerful complement to it. Whether you are trying to conceive naturally, preparing for IVF, or optimising your health ahead of any conception attempts, what you eat can help you improve hormonal and metabolic factors that drive PCOS-related infertility.

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Why PCOS Affects Fertility

The core problem: disrupted ovulation

PCOS is a leading cause of disrupted or absent ovulation in women trying to conceive. Without regular ovulation, conception becomes significantly impaired.

The main drivers of ovulatory dysfunction in PCOS are:

Insulin resistance: The majority of women with PCOS have some degree of insulin resistance. This causes elevated insulin which stimulates the ovaries to produce excess androgens (testosterone), subsequently suppressing normal follicle development and ovulation. This insulin-androgen cycle is central to PCOS-related infertility.

Elevated androgens: High testosterone disrupts the hormonal signalling required for a follicle to mature and release an egg. In PCOS there is also more biologically active testosterone circulating in the body.

Chronic low-grade inflammation: PCOS is associated with persistent inflammatory activity, which impairs both ovarian function and endometrial receptivity (the environment into which an embryo implants).

Elevated AMH and disrupted LH:FSH ratio: Women with PCOS typically have elevated anti-Müllerian hormone (AMH) and an elevated LH:FSH ratio.

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Fertility outcomes in PCOS

With appropriate management, many women with PCOS can and do conceive. However, PCOS is also associated with an increased risk of pregnancy complications including gestational diabetes, preeclampsia, and miscarriage. For this reason, preconception health optimisation is particularly important, not just for conception, but for pregnancy outcomes too.

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The Role of Nutrition in PCOS Fertility

Nutrition influences fertility in PCOS through several interconnected pathways: improving insulin sensitivity, reducing androgens, lowering inflammation, supporting regular ovulation, and improving egg quality.

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The Mediterranean Diet: Strongest Evidence for PCOS Fertility

Among all dietary patterns studied in women with PCOS and fertility challenges, the Mediterranean dietary pattern has the most consistent evidence base.

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Why it works 

The Mediterranean diet addresses three key mechanisms:

Insulin sensitivity: Slow-release carbohydrates and high fibre from wholegrains, legumes and vegetables, along with adequate protein and healthy fats, support glycaemic control and improve cellular insulin signalling.

Anti-inflammatory effect: Omega-3 fatty acids from oily fish, polyphenols from extra virgin olive oil and herbs, and antioxidants from a wide variety of fruit and vegetables collectively reduce the chronic inflammation that impairs ovarian and endometrial function.

Hormonal balance: Evidence shows Mediterranean eating patterns are associated with reduced free testosterone, improved SHBG, and more regular menstrual cycles.

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Key Nutrients for PCOS Fertility

Folate (or folic acid – the synthetic form found in supplements)

Essential for all women trying to conceive. Beyond preventing neural tube defects, research in women with PCOS suggests folic acid may also help improve ovulatory function and reduce elevated homocysteine levels - particularly relevant if taking metformin. Women with the MTHFR gene variant may benefit from the active form, methylfolate, rather than standard folic acid. 

Food sources: Dark leafy greens, legumes, fortified foods

Supplementation: 400mcg daily folic acid (or methylfolate if indicated) at least three months before conception and continuing through the first 12 weeks of pregnancy. Note: Women taking metformin should also have their B12 levels monitored regularly, as metformin can impair B12 absorption over time.

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Omega-3 Fatty Acids (EPA & DHA)

Omega-3s can reduce inflammation and triglyceride levels, support egg quality, and evidence from IVF studies suggests benefits for fertilisation and embryological outcomes. Women with PCOS who don't regularly eat oily fish should consider supplementation.

Food sources: Oily fish, walnuts, flaxseed, chia seeds (though plant-based omega-3s have a lower conversion rate to EPA and DHA - the forms the body most benefits from).

Supplementation: Consider if oily fish intake is less than 1–2 portions per week. Avoid cod liver oil as it can contain high vitamin A levels which are contraindicated in pregnancy. Algal omega-3 supplements are available for those who are vegan or prefer to avoid fish oil.

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Vitamin D

Vitamin D deficiency is extremely common in women with PCOS and is independently associated with impaired fertility. Vitamin D plays a role in follicle development, ovulation, endometrial function, insulin sensitivity, and bone health. Supplementation in women with deficiency has been shown to improve menstrual regularity, follicular growth, and IVF pregnancy rates.

Food sources: Oily fish, eggs, fortified foods

Supplementation: Testing is recommended; supplementation should be guided by blood levels. All adults in the UK are advised to supplement 10mcg (400IU) daily, particularly in winter months (October–March).

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Inositol

Inositol -especially myo-inositol, or a combination of myo-inositol and d-chiro-inositol in a 40:1 ratio- has the strongest evidence base of any supplement for PCOS, and its benefits extend to fertility. Apart from improved insulin sensitivity, research demonstrates improved ovulation, reduced testosterone, better egg quality and IVF response.

Supplementation: Typically 2-4g myo-inositol daily. A combination with d-chiro-inositol in a 40:1 ratio mirrors the body's natural ratio and is widely used in clinical research.

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Antioxidants 

Oxidative stress is elevated in PCOS and impairs both oocyte quality and endometrial function. A diet rich in antioxidants helps protect eggs from oxidative damage during follicular development.

Food sources: Colourful vegetables and fruit, extra virgin olive oil, nuts, seeds

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Weight, Fertility, and PCOS: An Important Nuance

Research suggests that for women with PCOS who are above a healthy weight, modest weight loss (5-10% of body weight) can meaningfully improve ovulatory function, hormone levels, and fertility outcomes, with studies showing improved conception and live birth rates following preconception weight reduction.

However, given weight loss can be particularly difficult in PCOS (due to metabolic and hormonal nature of the syndrome) it is equally important to understand that:

• Ovulation restoration can occur with dietary improvements and insulin sensitisation without weight loss. 
• Severe calorie restriction is counterproductive: physiologically, it elevates cortisol, impairs thyroid function, can lead to nutritional deficiencies and worsen the hormonal disruption already present in PCOS; psychologically, it is rarely sustainable long-term and can trigger or exacerbate disordered eating patterns, both of which ultimately undermine fertility.

The goal is nutritional quality and metabolic health, not aggressive dieting. A sustainable, anti-inflammatory dietary approach that improves insulin sensitivity can support fertility regardless of whether weight changes occur.

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Preparing Nutritionally for IVF with PCOS

Women with PCOS face specific challenges in IVF. Nutritional preparation 3-6 months in advance can meaningfully support outcomes.

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Preconception nutrition priorities for IVF:

• Stabilise blood sugar: a consistent, low-glycaemic index eating pattern can help reduce insulin and androgen levels, and improve ovarian response to stimulation
• Establish an anti-inflammatory foundation: Mediterranean-style eating in the months before egg collection can reduce systemic inflammation
• Optimise key nutrients: folate/methylfolate, vitamin D, vitamin B12 (if vegan or on metformin), inositol, and omega-3s are the most evidence-supported supplements for women with PCOS undergoing IVF
• Adequate protein intake: supports oocyte development and helps with appetite and glycaemic control
• Minimise alcohol: alcohol consumption is associated with reduced IVF success rates
• Limit caffeine: current guidance recommends no more than 200mg per day (roughly 1-2 cups of coffee) when trying to conceive

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When to Work With a Fertility Dietitian

Nutritional management of PCOS fertility is individual. The right approach depends on your specific metabolic profile, blood results, any medications you're taking, as well as your food preferences and lifestyle.

Consider working with a specialist dietitian if you:

• Have PCOS and have been trying to conceive for 6 months or longer
• Are preparing for IVF and want to optimise your nutritional status
• Have insulin resistance, elevated HbA1c, or dyslipidaemia alongside PCOS
• Are unsure which supplements are appropriate for your situation
• Have a history of disordered eating alongside PCOS
• Want a clear, evidence-based preconception nutrition plan

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Key Takeaways

1. PCOS is a major cause of anovulatory infertility. Nutrition directly addresses the underlying mechanisms
2. Improving insulin sensitivity is the most important nutritional goal for ovulation restoration
3. Mediterranean-style eating has the strongest evidence for PCOS fertility outcomes
4. Key nutrients -folate, vitamin D, inositol, omega-3s- specifically support egg quality and conception
5. Nutritional preparation 3-6 months before IVF can meaningfully improve outcomes
6. The goal is metabolic and hormonal health, not aggressive calorie restriction

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Work With a Specialist

If you are navigating fertility challenges with PCOS and would like personalised nutritional support, Maria Kolotourou is a Registered Dietitian specialising in women's hormonal health, working with women alongside their fertility treatment.

Explore her Fertility & Pregnancy Nutrition Programme or book a free 15-minute discovery call to discuss how nutrition can support your PCOS fertility journey.

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Disclaimer: This article is for educational purposes only and does not constitute individualised medical or dietetic advice. Always consult a qualified healthcare professional before making changes to your diet or supplement regimen, particularly if you are undergoing fertility treatment or taking medication.

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References

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7. Gitsi E, Livadas S, Argyrakopoulou G. Nutritional and exercise interventions to improve conception in women suffering from obesity and distinct nosological entities. Front Endocrinol (Lausanne). 2024 Jun 28;15:1426542. doi: 10.3389/fendo.2024.1426542. PMID: 39006367; PMCID: PMC11239444.
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