Egg Quality and Natural Support

How Egg Quality Actually Works

A woman is born with all the eggs she will ever have — roughly 1–2 million primordial follicles at birth, declining to about 300,000 by puberty and around 25,000 by age 37. But the eggs themselves are not "old" in any simple sense: each one sits in an arrested state until recruited into the final 90-day maturation window in the months before it is ovulated. During that window, the egg's mitochondria, cytoskeleton, and chromosome-segregation machinery are uniquely vulnerable to oxidative damage and metabolic disturbance. This is why interventions that take 3–4 months to show effects — and why women who change their diet, supplements, and lifestyle 90+ days before trying to conceive consistently see better outcomes than those who wait until they are already trying.

The two biggest determinants of egg quality during this maturation window are mitochondrial energy production and protection from oxidative stress. The mature human oocyte contains roughly 100,000 mitochondria — more than any other cell in the body — because the energy demands of meiosis (correctly separating chromosomes) and the early cell divisions after fertilisation are enormous. When mitochondrial ATP production falls, chromosome segregation errors rise sharply, leading to aneuploidy (the wrong chromosome count), which is the single biggest cause of failed implantation, early miscarriage, and age-related fertility decline.

The Fertility Diet: What 17,544 Women Showed

The Nurses' Health Study II followed 17,544 women trying to conceive over eight years and identified a dietary pattern linked to dramatically lower rates of ovulatory infertility. [1] Compared to women in the bottom quintile of "fertility diet" adherence, women in the top quintile had a 66% lower risk of ovulatory infertility and 27% lower risk of infertility from any cause. The pattern was characterised by:

• More monounsaturated and less trans fats
• More vegetable than animal protein
• More high-fibre, low-glycaemic carbohydrates
• More full-fat (rather than low-fat) dairy
• More iron from plant sources
• A daily multivitamin (folate appears to be the key driver here)

This pattern looks very similar to the Mediterranean diet, which a Spanish nested case-control study independently confirmed: women in the highest tertile of Mediterranean diet adherence were 44% less likely to consult for difficulty conceiving compared to the lowest tertile. [2] The biological logic is straightforward — these dietary patterns reduce systemic inflammation, stabilise insulin (excess insulin suppresses ovulation through effects on LH and free testosterone), and supply the methyl-donor B vitamins, antioxidants, and omega-3 fats that maturing follicles need.

See our Mediterranean diet page for more on the broader pattern, and our folate page for why the multivitamin element matters.

CoQ10: Powering the Aging Oocyte

CoQ10 (ubiquinone/ubiquinol) is a fat-soluble component of the mitochondrial electron transport chain and a potent antioxidant. As women age, follicular fluid CoQ10 levels decline, and the oocyte's mitochondria become less efficient at producing the ATP required for accurate chromosome segregation. A small randomised pilot in women aged 38–46 undergoing IVF found that 600 mg/day of CoQ10 for 60 days before retrieval reduced the proportion of aneuploid embryos compared to controls (46.5% vs 62.8%), although the trial was halted early and underpowered for definitive conclusions. [5]

The clinical doses used in trials are 200–600 mg/day of ubiquinone (or 100–300 mg of the more bioavailable ubiquinol form), started at least 60–90 days before a conception attempt or IVF cycle. Combined with the timeline of follicle maturation, this is one of the better-supported supplements for women 35+.

Myo-Inositol: The PCOS Game-Changer

For women with polycystic ovary syndrome (PCOS) — the most common cause of ovulatory infertility — myo-inositol is among the best-supported natural interventions. A 2017 meta-analysis of nine randomised controlled trials found that myo-inositol significantly improved ovulation, restored regular cycles, and improved oocyte and embryo quality in PCOS patients. [4] Clinical doses are 2 g taken twice daily, often combined with 50 mcg D-chiro-inositol in a 40:1 ratio. The mechanism is restoration of normal insulin signalling within ovarian theca and granulosa cells, which corrects the hyperandrogenism and ovulatory dysfunction that defines the syndrome.

See our PCOS page and our inositol page for more.

Vitamin D: Don't Skip the Test

A 2018 systematic review and meta-analysis of 11 IVF studies found women with replete vitamin D status (>30 ng/mL) had significantly higher rates of clinical pregnancy and live birth compared to women who were deficient (<20 ng/mL), with the effect more pronounced in women undergoing fresh transfers. [6] Vitamin D receptors are expressed on ovarian granulosa cells, the endometrium, and the placenta, and adequate vitamin D appears important for follicular maturation, endometrial receptivity, and early implantation. Get a 25(OH)D blood test rather than guessing — most women trying to conceive in non-tropical latitudes need 2,000–4,000 IU/day to reach the 30–60 ng/mL range associated with the best outcomes.

See our vitamin D page for testing and dosing details.

Omega-3: The Fecundability Boost

Omega-3 fatty acids — particularly EPA and DHA from cold-water fish — are essential for cell membrane fluidity, anti-inflammatory eicosanoid production, and the corpus luteum's progesterone output after ovulation. A 2022 prospective cohort of 900 women trying to conceive found that those taking omega-3 supplements were 1.5 times more likely to conceive in any given cycle (fecundability ratio 1.51, 95% CI 1.12–2.04) compared to non-users, after adjusting for diet, BMI, and other factors. [7] Two to three grams per day of combined EPA+DHA from a quality fish oil, krill oil, or algae oil (for vegans) is the typical clinical target.

See our omega-3 page and our wild salmon page for sources.

Reducing Pesticide Exposure

A 2018 prospective cohort of 325 women undergoing IVF at Massachusetts General Hospital found that women in the highest quartile of high-pesticide-residue fruit and vegetable intake had 18% fewer pregnancies and 26% fewer live births compared to women in the lowest quartile. [3] High-pesticide-residue items include conventionally grown strawberries, spinach, kale, peaches, pears, apples, grapes, cherries, peppers, and tomatoes. Switching these to organic — or using the EWG's "Dirty Dozen" list — is one of the more cost-effective interventions in the literature, with replicated effects on actual pregnancy outcomes rather than just biomarkers.

See our organic food page, glyphosate page, and atrazine page for more on specific pesticide concerns.

Sleep, Stress, and the HPA-Ovarian Axis

Cortisol — the body's main stress hormone — communicates directly with the ovary. Chronic elevations suppress GnRH from the hypothalamus, which downregulates LH and FSH, which in turn impairs follicle recruitment, ovulation, and corpus luteum function. Women trying to conceive should treat sleep and stress as fertility variables: aim for 7–9 hours of consistent sleep, address chronic stressors where possible, and consider gentle practices like yoga, meditation, or walking rather than over-exercising. High-volume endurance training and severe caloric restriction can both suppress ovulation through low energy availability — this is one of the few areas where "more exercise" can be counterproductive.