Evidence-Based Nutrients to Support Egg Quality, Ovulation, and Natural Fertility in Women Over 35
It is a reality that aging is one of the biggest contributors to fertility issues in women. It is also a reality that more women are choosing to try for children later in life.
Women are born with a certain number of eggs (oocytes) – about 1 to 2 million egg.
This number decreases around 500,000 by puberty and continues to decrease each year. After age 30 but egg quality and egg quantity (ovarian research) decrease significantly:
· By age 30 a woman has roughly 10% of the eggs she was born with left
· By age 37 this decreases to about 2.5%
· age 40 this decreases to about 1%
Guidelines often recommend seeking fertility help after 6 months of trying if you’re over 35 (as opposed to 12 months for younger women). In reproductive medicine, 35 is the main cutoff when doctors start classifying pregnancy as “advanced maternal age.”
At this point, it is important to highlight that natural conception is possible after age 35 or 40 and that natural conception is possible even with very few eggs. But egg quality is crucial!
How do you known how many eggs you have?
The amount of eggs (ovarian reserve) can be estimated via
· Anti-Müllerian Hormone (AMH) blood tests -see this blog
· Antral Follicle Count (AFC) via ultrasound
If you are trying to conceive and over age 35 or 40, your reproductive doctor may recommend additional testing such as
· FSH (follicle stimulating hormone) & estradiol
· Thyroid testing
How to improve fertility after 35 and 40
Lifestyle is crucial - start as early as possible!
· Healthy weight
Both underweight and overweight can disrupt ovulation.
1. Exercise aim for 20 to 30 minutes of moderate movement daily
2. Sleep – aim for 7 to 9 hours of sleep in complete darkness every night to improve hormone and metabolic health
3. Stress reduction – think of mindfulness, yoga, meditation, even a walk with a friend
4. Avoid smoking
5. Moderate or no alcohol – 3 to 4 drinks max spread throughout the week
6. Moderate or no caffeine (200mg is a sensible limit which is 2 cups of coffee
7. Minimise environmental toxins (microplastics BPA, pesticides) – avoid heating food in plastic containers, plastic utensils
8. Track Ovulation
9. Manage conditions that affect fertility:
o Polycystic Ovary Syndrome (PCOS)
o Endometriosis
o Thyroid Disease
o Uterine Fibroids
·
· Consider Fertility Treatments Earlier
If you are over 35 or 40 and trying to conceive naturally with no success, fertility treatments can help:
· Ovulation induction medications
· IUI (Intrauterine Insemination)
· IVF (In Vitro Fertilization), incuding ICSI
After 40, many doctors recommend considering IVF sooner, because success rates per cycle are higher than waiting with natural attempts.
· Fertility Supporting nutrition
Foods that support fertility:
· Leafy greens e.g. spinach, kale, broccoli
· Fatty fish e.g. salmon, sardines, mackerel
· Nuts and seeds especially linseed, chia seed and walnuts
· Whole grains e.g. oats, wholemeal pasta,
· Berries e.g. blueberries, strawberries, raspberries etc.
Foods that reduce fertility:
· Highly processed foods e.g. packaged snacks, mass-produced bread, sausages, ready-meals etc.
· Trans fats e.g. beef, baked goods
· Excess sugar e.g. sweets, biscuits, soft drinks
The nutrients which have been shown in human research studies in women older than 35 or 40 to improve ovulation, egg health and overall fertility include:
· Q10 – at least 100mg daily
· Alpha Lipoic acid – 600 to 800mgdaily
· Carnitine at least 1000mg daily
· Myo-inositol 1,000 to 2000mg daily
· N acetyl-cysteine – 600mg daily
· Omega 3 – 1000mg daily
· Vitamin B9 (folate) 400mcg daily
· Vitamin D 50mcg (2,000 IU) daily
· Melatonin – 2 to 5mg every evening
Coenzyme Q10
Coenzyme Q10 supplementation for 2 months before an IVF cycle in women aged Women aged 35–43 years reported lower aneuploidy rates and higher pregnancy rates. This specific study is on the few that specific examined women over ag 35
Coenzyme Q10 supplementation increased follicular fluid CoQ10 content and improved oxidative metabolism. These benefits were even greater in women over 35 years.
A 2020 review of 5 trials of Coenzyme 10 supplementation from Greek researchers reported that increased pregnancy rates, including in women with poor ovarian response and PCOS
A 2023review of scientific studies published in the journal Human Fertility from UK researchers reported coenzyme Q10 supplementation could improve fertilization/embryo maturation rates and improve markers of oocyte quality in women aged 31 and over (many of the women were over 35).
Alpha Lipoic acid
A 2020 study in the Journal of Clinical Medicine reported that in overweight/obese women without PCOS (average age of 36) that myo-inositol + alpha lipoic acid + folic acid vs Resulted in improved egg quality compared to folic acid alone
Carnitine
A 2024 study reported the in 515 women with an average age of 35, carnitine supplementation led to:
· improved markers of ovarian function
· better follicular development
· higher ovarian response during IVF stimulation.
The authors concluded L-carnitine may help alleviate ovarian dysfunction and improve reproductive potential in women over 35.
Carnitine is involved in mitochondrial fatty-acid transport, which is crucial for egg energy metabolism.
Age-related egg quality decline is strongly linked to mitochondrial dysfunction.
Researchers think carnitine may help by:
1. Improving mitochondrial ATP production
2. Increasing fatty-acid oxidation in oocytes
3. Reducing oxidative stress
4. Improving endometrial receptivity.
These mechanisms are especially relevant in advanced maternal age fertility research.
A 2025 systematic review of 8 different randomized trials with over 1,000 women evaluated L-carnitine supplementation in fertility treatment. Carnitine supplementation increased:
· ovulation rates
· progesterone levels
· number of mature follicles
· clinical pregnancy rates.
Although this review included studies with women of various ages, the benefits of carnitine appear related to improved insulin sensitivity and improved mitochondrial metabolism which are highly relevant for age-related fertility decline.
In 2013, research from Hungary measured carnitine levels in follicular fluid during IVF and found that carnitine metabolism is closely linked with embryo developmental competence.
These researchers suggested that supplemental L-carnitine could optimize early embryo development by improving cellular energy metabolism.
L-carnitine is involved in mitochondrial fatty-acid transport, which is crucial for egg energy metabolism.
Age-related egg quality decline is strongly linked to mitochondrial dysfunction.
Researchers think carnitine may help by:
1. Improving mitochondrial ATP production
2. Increasing fatty-acid oxidation in oocytes
3. Reducing oxidative stress
4. Improving endometrial receptivity.
These mechanisms are especially relevant in advanced maternal age fertility research.
Myo-inositol
A 2012 study published in the journal Reproductive Biology and Endocrinology, Myo-compared myo-inositol and folic acid vs folic acid alone in women aged up to 40
Women taking myo-inositol:
· needed less rFSH hormone injections to reach egg maturation - This suggests the ovaries responded more efficiently.
· had fewer eggs retrieved - This sounds bad at first, but IVF success depends more on egg quality than quantity
· Slightly better implantation - Embryos from the myo-inositol group may have implanted slightly more often
· Pregnancy rates were the same - There was no significant difference in pregnancy rates between groups. So despite having fewer eggs, the myo-inositol group still achieved similar outcomes.
Based on this study and additional research with myo-inositol, supplementing with myo-inositol might:
· Make ovaries more sensitive to stimulation
· Reduce the amount of fertility drugs needed
· Possibly improve egg quality
· Maintain normal pregnancy rates
So instead of producing many eggs, the body might produce fewer but potentially better ones.
A 2015 study published in the Journal of Ovarian Research Myo-inositol supplementation in women age of 30 to 42 led to:
· higher number of mature eggs capable of fertilization
· higher ovarian sensitivity index
· improvement in ovarian sensibility to gonadotropin medications
In a 2020 study published in Journal of Gynecology Obstetrics and Human Reproduction, myo-inositol supplementation in women with an average age of 38 resulted in improved fertilization rate
· improved embryo quality
· higher pregnancy rate
in a 2021 study published in the journal Reproductive Biology and Endocrinology, Myo-inositol supplementation in women with an average age of 35 led to :
· more oocytes retrieved,
· higher number of MII oocytes,
· higher number of embryos transferred,
· higher ovarian sensitivity index
· lower required dose of gonadotropin
· higher fertilization rate
· higher pregnancy rate
a 2022 study published in the International Journal of Reproductive Biomedicine reported the myo-inositol could
· increase the total number of eggs
· the number of high quality eggs
· increase clinical pregnancy
· increase live birth rates
A 2017 review of studies (meta analysis) of 13 trials involving over 1,400 women aged 31 to 36, that myo-inositol supplementation
· reduced the required amount of stimulation drugs
· improved the quality of embryos
· increased clinical pregnancy rate
Vitamin B9
A 2014 study From Harvard examined 232 women (average age of 35) and reported that higher folate intake from diet+ supplements was associated with higher rates of
· fertilized egg implantation,
· clinical pregnancy,
· live birth.
A 2022 from the Environment and Reproductive Health Study among 552 women (average age 35) and reported that ‘higher intake of folate, particularly from supplements, was associated with higher ovarian reserve as measured by AFC (antral follicle count)
Another prospective study (BioCycle Study) examined hormonal cycles in omen aged 18 to 44 and found that higher supplemental folate was associated with
· Higher luteal progesterone (this suggests health ovulation)
· Reduced likelihood of ovulation failure
These studies highlight the importance of folate for all but especially for women over 35 with roles such as
· improving oocyte quality
· improving embryo development
· reducing early embryo failure.
· Improving follicular development
· Improving ovarian aging markers
· ovulatory function
· luteal phase hormones
Vitamin D
A 2019 cohort study of 1,191 women aged up to 40 reported that the women with adequate vitamin D levels were more likely to achieve pregnancy and a live birth than the women with vitamin D deficiency
Another 2019 cohort study of 500 women, many of whom were in their mid 30s, reported that pregnancy rates were 65% lower in women with vitamin D deficiency. The researchers wrote: ‘Vitamin D deficiency and insufficiency are common in women undergoing assisted reproductive treatments. Vitamin D deficiency could be an important condition to treat in women considering fertility treatment’.
A 2022 study of vitamin D levels in women undergoing IVF with a median age of 36 reported that birth rates were 15% lower in women with vitamin D deficiency.
A 2025 study of over 300 women with a median age of 36 reported that pre-conception vitamin D deficiency is associated with an increased risk of hypertensive disorders in pregnancy in women undergoing in vitro fertilization with fresh embryo transfer.
In a large 2025 cohort study of 1,459 women. The researchers examined the effects of vitamin D levels of pregnancy rates in women older or younger than 35. Vitamin D deficiency was associated with significantly worse clinical pregnancy outcomes specifically in women over 35. The researchers concluded: ‘Vitamin D deficiency appears to lead to poorer clinical pregnancy outcomes in patients of advanced age’
Omega 3
A 2022 study of 900 women aged 30 to 44 reported that women using omega-3 supplements had 50% higher probability of conceiving per cycle compared with non-users
A 2026 study of 180 women aged 18 to 42 undergoing IVF assessed the effect of the pro-fertility diet + 1,000mg omega 3 daily for 60 days before IVF. The diet + omega 3 supplement led to
· significantly higher fertilization rates
· embryo formation rates
· increased number of embryos formed
· the proportion of grade A embryos was markedly higher
The ‘profertility diet’ is defined as:
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Less |
More |
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High pesticide fruit & veg |
Low pesticide fruit & veg |
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Meat |
Vitamin B9, B12 and D3 |
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Whole grains |
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Seafood |
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Dairy |
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Soy foods |
· A 2023 trial with women with PCOS (average age = 34) reported that omega 3 supplementation increased pregnancy rates by 50% compared to placebo
Melatonin
NAC (N-acetyl cysteine)
A 2022 study in the journal Frontiers in Medicine specifically examined the effect of NAC in in 200 ‘women with advanced age’, average age 38.
NAC significantly increased the number of high-quality blastocysts (better embryo development).
The Researchers also examined why. They found:
o increased glutathione levels in follicular fluid
o improved mitochondrial DNA copy number in granulosa cells (cells surrounding the egg).
The authors proposed that NAC improves egg quality by reducing oxidative stress in the ovarian follicle, which becomes more pronounced with age.
