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Signs of Bad Egg Quality & What They Mean for Fertility

When you’re trying to conceive, it’s natural to wonder about your egg quality. While age plays a role, many factors influence the health of your eggs — and understanding these can help you make informed, proactive choices.

Author

Tassia O’Callaghan

Reviewed by

Kayleigh Hartigan

15 min read

Published 27 October 2025

Spotlight:

  • Egg quality refers to how likely an egg is to fertilise, develop into a healthy embryo, and result in pregnancy — it’s about potential, not perfection.

  • Quality depends on factors like chromosomal health, mitochondrial energy, and the egg’s structural stability — all of which decline naturally with age.

  • After 35, eggs are more prone to chromosomal errors, but lifestyle, diet, and tailored fertility care can still improve outcomes.

  • There’s no single test for egg quality — fertility specialists assess it through hormone levels, ultrasound scans, and IVF results.

  • Poor egg quality doesn’t mean you can’t conceive; many people still achieve pregnancy with medical support, lifestyle changes, or donor eggs.

  • Supporting egg health takes time — eggs mature over roughly three months, so small, consistent changes can make a real difference.

What is egg quality?

Every human begins life as a single cell — an egg, or oocyte — one of the most extraordinary cells in the body. Unlike any other, an egg has the potential to generate an entirely new individual once it’s fertilised. But not all eggs have the same potential.

Egg quality describes how capable an egg is of being fertilised, developing into a healthy embryo, and ultimately leading to pregnancy. A good-quality egg has the right number of chromosomes, healthy mitochondria to power cell division, and intact structures that keep its genetic material stable as it matures. [1,2]

What makes a “good-quality” egg?

A good-quality egg is one that can complete fertilisation and early cell division without chromosomal errors. That depends on three main biological factors:

  • Chromosomal integrity: Eggs must split their chromosomes perfectly during meiosis. If separation errors occur, the resulting embryo may have too many or too few chromosomes (aneuploidy), often leading to failed implantation or miscarriage. [3]

  • Mitochondrial function: Mitochondria are the egg’s energy engines. They fuel every stage from fertilisation to the first cell divisions. Over time, mitochondrial DNA accumulates damage from oxidative stress, which can reduce energy output and developmental potential. [4]

  • Cohesion and spindle stability: Protein “glue” (cohesins) holds chromosomes together until they’re pulled apart by the spindle fibres. With age, cohesins weaken, and spindles become less precise — a key reason egg quality drops after 35. [5]

Other elements also matter, such as telomere length (the protective caps on DNA) and a balanced internal environment supported by surrounding follicle cells. [6,7]

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What causes poor egg quality?

Egg quality naturally declines with age because the DNA repair systems and mitochondria within eggs weaken over time. However, other factors can also play a part:

  • Age: The most significant factor. After 35, the proportion of genetically normal eggs decreases rapidly. [8]

  • Chromosomal abnormalities: Errors can occur when eggs mature, often linked with age. [9]

  • Oxidative stress: Damage from free radicals (caused by smoking, excessive alcohol, poor diet, or pollution) can impact egg DNA. [10,11,12]

  • Medical conditions: Endometriosis, PCOS, autoimmune conditions, or thyroid issues can influence quality. [13,14]

  • Environmental toxins: Long-term exposure to plastics, pesticides, or heavy metals may contribute, though data is limited. [15,16]

Does PCOS cause poor egg quality?

PCOS doesn’t automatically cause poor egg quality, but it can disrupt how eggs mature. People with PCOS often produce more eggs, yet many are immature due to hormonal imbalance and disrupted follicle growth. Research shows that while the number of eggs retrieved in IVF is higher, their overall quality is usually similar to those without PCOS. [17]

That said, factors linked to PCOS — like insulin resistance, raised androgens, and inflammation — can affect the environment eggs develop in. Managing these through lifestyle changes, medication, and balanced nutrition can help improve egg maturity and ovulation. With the right support, many people with PCOS conceive successfully. [18]

Does stress affect egg quality?

Stress can influence egg quality in subtle but meaningful ways. When psychological stress becomes chronic, it raises levels of cortisol — a hormone that can disrupt normal ovarian function. High cortisol may reduce oestrogen production in the follicle and interfere with communication between the egg and surrounding granulosa cells, which are essential for nourishment and maturation. Over time, this can make it harder for eggs to mature fully or fertilise successfully, though not everyone is affected in the same way. [19,20]

What are the symptoms of poor egg quality?

There are no visible symptoms — poor egg quality is typically identified through fertility testing after egg retrieval. Sometimes, not conceiving for an extended period of time, or repeated chemical pregnancies or miscarriages can also be a sign of poor egg quality, although it’s often hard to tell, unless a biopsy is performed.

Can poor egg quality affect fertility?

Poor egg quality can have a direct impact on fertility because it affects an egg’s ability to be fertilised and develop into a healthy embryo. Eggs with chromosomal abnormalities or damaged mitochondria may not divide properly after fertilisation, which can lead to lower fertilisation rates, failed implantation, or early miscarriage. In IVF, this often shows up as embryos that stop growing before reaching the blastocyst stage or transfers that don’t result in pregnancy. These challenges become more common with age, but they can also occur in younger people due to environmental, hormonal, or lifestyle factors. [21]

That said, poor egg quality doesn’t necessarily mean the end of your fertility path. Many people still conceive — naturally or with medical support — especially with early diagnosis and a personalised treatment plan. Clinics may adapt stimulation protocols, add supplements, or recommend donor eggs depending on your circumstances. Focusing on egg health, overall wellbeing, and working closely with your fertility team can all improve your chances of a successful pregnancy.

How is egg quality diagnosed?

Egg quality can’t be measured by a single test — there’s no way to see inside an egg and assess its potential without fertilisation. Instead, fertility specialists look at a combination of hormone levels, ultrasound findings, and treatment outcomes to build a picture of your overall ovarian health. These markers help estimate both the quantity and potential quality of your eggs, giving doctors a sense of how your ovaries are functioning and how you might respond to fertility treatment.

  • AMH (Anti-Müllerian Hormone): Produced by follicles in your ovaries, AMH gives an estimate of your remaining egg supply. Lower levels can suggest a reduced reserve, though AMH doesn’t directly measure egg quality.

  • FSH (Follicle-Stimulating Hormone): Tested early in your cycle, high FSH levels may indicate your ovaries are working harder to stimulate egg growth — often a sign of lower reserve. [22]

  • AFC (Antral Follicle Count): A transvaginal ultrasound counts the small, fluid-filled follicles that house developing eggs, helping to predict your response to stimulation.

  • IVF outcomes: If you’ve had treatment, how your eggs fertilise and develop into embryos provides valuable, real-world insight into quality.

  • Genetic testing (PGT-A): Used during IVF, this identifies embryos with the correct number of chromosomes — one of the clearest reflections of underlying egg health.

How to check egg quality at home

There’s no at-home test that can directly measure egg quality — that’s something only seen once an egg has been fertilised in a lab. However, there are ways to get a general sense of your reproductive health. Home AMH tests can give an indication of your ovarian reserve (how many eggs you’re likely to have left), though they don’t reveal whether those eggs are genetically healthy. Ovulation predictor kits can help you understand if and when you’re ovulating regularly — a good sign that your hormonal cycle is functioning as it should.

Some people also track basal body temperature, cervical mucus, or use fertility apps to monitor cycle patterns over time. While these methods can be empowering, it’s important to interpret them carefully. If you’re concerned about your results, struggling to conceive, or want a clearer picture of your egg health, a fertility clinic can provide more accurate testing and personalised advice.

Can you treat poor egg quality?

Egg quality can’t be fully “reversed,” but you can support the environment eggs develop in. Each cohort takes roughly 3 months to mature, so what you do now can influence the eggs you ovulate in a few cycles’ time. Small, consistent changes — alongside evidence-based medical care — tend to work best. [23]

  • Eat for cell health. A balanced pattern rich in vegetables, fruit, whole grains, legumes, nuts, and oily fish supplies antioxidants and micronutrients that help protect cells from oxidative stress. This is the same “healthy, balanced diet” UK guidance recommends when trying to conceive.

  • Avoid smoking and limit/avoid alcohol. Both are linked with reduced fertility and poorer treatment outcomes; UK guidance advises avoiding alcohol altogether when trying to conceive and stopping smoking for both partners.

  • Prioritise sleep and stress management. Consistent sleep and stress-reduction strategies (breathwork, CBT-style tools, gentle movement) help regulate hormones that orchestrate follicle development. They’re sensible first-line measures recommended in pre-conception lifestyle advice from UK health services. [24]

  • Move regularly — moderately. Regular, moderate activity can improve time to pregnancy and overall reproductive health (think brisk walking, cycling, swimming). Aim for movement that raises your heart rate but still lets you talk. [25]

  • Medications (with a specialist). Androgen/DHEA “priming” and growth hormone (HGH) are sometimes offered in IVF for selected low-response cases, but UK regulators currently rate these as add-ons with limited evidence for improving live birth rates. Discuss potential benefits/risks and costs with your clinic before considering them. [26,27]

  • Choose supplements with care. (Please note, we don’t recommend taking new supplements without the advice of a medical professional.)
    • Folic acid (400 μg/day) pre-conception is recommended for everyone trying to conceive. [28]
    • Vitamin D may also be advised depending on season and individual need. [29]
    • Coenzyme Q10 (CoQ10) has emerging — but not definitive — evidence for egg/embryo support in some studies; safety at typical doses is generally good, but it’s still not an NHS- or HFEA-endorsed fertility treatment. Discuss dose and timing with your clinician, especially if you’re on other medicines. [30]

But ultimately, improving egg quality is a personal journey — it’s best to speak with your healthcare provider or a fertility doctor for more individualised guidance on how you can best improve your egg quality.

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Can you conceive with poor egg quality?

Yes — it’s still possible to conceive with poor egg quality. While lower-quality eggs are less likely to fertilise, implant, or develop into a healthy pregnancy, conception can and does happen. Even if only a small proportion of eggs are chromosomally normal, these are the ones with true pregnancy potential.

Fertility treatments like IVF or ICSI can help identify and select the healthiest embryos, increasing the chance of success. In some cases, using donor eggs may offer a higher likelihood of pregnancy — particularly for those whose own eggs have been affected by age or medical conditions — and the HFEA reports that success rates with donor eggs are often higher than IVF using a patient’s own. [31]

Even outside of treatment, there’s much you can do to support your reproductive health. A balanced diet, stopping smoking, reducing alcohol, managing stress, and maintaining a healthy weight can all support ovulation and hormone balance, which are vital for conception. [23]

So while poor egg quality can make the journey more complex, it doesn’t make it impossible — with medical support and a holistic approach to health, many people go on to conceive successfully.

How does egg quality affect fertility treatment?

Egg quality plays a crucial role in how well fertility treatments work. When eggs are healthy, they’re more likely to fertilise successfully, develop into chromosomally normal embryos, and implant in the womb. When quality is lower, the chances of fertilisation or embryo development may decrease — but success is still possible. Your fertility team can adapt treatment plans, adjust medication doses, or recommend specific approaches to maximise your chances.

IVF (In Vitro Fertilisation)

During IVF, eggs are collected and fertilised with sperm in a lab to create embryos. If egg quality is reduced, fewer embryos may reach the stage suitable for transfer or freezing, and implantation rates may be lower. However, advances in lab techniques and stimulation protocols mean that even with a smaller number of viable eggs, success is possible. The HFEA reports that IVF success rates vary mostly by age, with around 36% of cycles leading to a live birth for women under 35, compared to 32% for those over 35, largely due to changes in egg quality. [31]

ICSI (Intracytoplasmic Sperm Injection)

ICSI is often used when sperm quality or fertilisation issues are suspected. A single sperm is injected directly into the egg, bypassing some of the barriers that might otherwise prevent fertilisation. For eggs with slightly compromised outer membranes or structural differences, ICSI can improve fertilisation rates and ensure that more embryos reach early development stages. The HFEA states that ICSI success rates are similar to IVF when used appropriately and can be particularly effective where fertilisation has previously failed. [31]

Egg freezing

Freezing eggs when they are younger helps preserve their quality for future use. As egg quality declines with age, eggs frozen earlier tend to fertilise and implant more successfully when thawed and used in treatment later. The HFEA advises that freezing before the mid-30s gives the best chance of future success, as the likelihood of retrieving genetically healthy eggs decreases over time. [32]

Donor eggs

When egg quality is significantly reduced, donor eggs can offer one of the highest chances of pregnancy. Donor eggs typically come from younger, screened donors, meaning they are more likely to result in healthy embryos and successful pregnancies. According to the HFEA, treatments using donor eggs have some of the highest live birth rates across all age groups. [31]

Your fertility clinic will personalise your treatment plan based on your test results, age, and response to medication. This might include adjusting stimulation drugs, adding supplements, or recommending complementary treatments to support egg health. While egg quality influences treatment outcomes, advances in reproductive medicine mean there are now more pathways than ever to help you build your family.

Summary

Egg quality is a crucial — but not definitive — part of fertility. While it declines with age, science and lifestyle support can make a measurable difference. With the right information, care, and community, you can take clear, confident steps toward your next chapter.

Egg quality FAQs

What is the best age for egg quality?

Egg quality is at its best in your 20s and early 30s, when most eggs are chromosomally normal and rich in the energy needed for healthy embryo development. From around 35 onwards, both egg number and quality gradually decline due to natural ageing processes within the ovaries — including spindle and mitochondrial changes that increase the risk of chromosomal errors. This doesn’t mean pregnancy is impossible: with tailored fertility treatment, lifestyle support, and in some cases donor eggs, many people still conceive successfully later in life. The HFEA reports that IVF success rates are around 32% under age 35 and 13% between 40–42, highlighting that while age plays a key role, individual fertility potential varies widely. [32]


Does it really take 3 months to improve egg quality?

Yes — roughly three months (or just over 120 days) is the time it takes for an egg to mature before ovulation. During this window, a group of microscopic primordial follicles gradually develop into pre-ovulatory eggs, influenced by hormones, nutrition, blood flow, and overall health. That’s why lifestyle and medical changes made today — like improving diet, reducing stress, or adjusting medication — can impact the quality of the eggs released in three months’ time. While you can’t change the DNA inside an egg, you can improve the environment it matures in, supporting healthier development and potentially better fertility outcomes.

How to tell if an egg is high quality

Egg quality can’t be measured perfectly, but embryologists look for visual signs of maturity and health under a microscope. A high-quality egg is usually mature, with a smooth outer shell (zona pellucida), an evenly textured cytoplasm, a small, clear perivitelline space, and an intact polar body. Using polarised light, clinics can also check for a well-formed meiotic spindle, which helps ensure chromosomes divide correctly. [33]

Researchers are also studying markers in cumulus cells and follicular fluid that may reflect egg health, but these tests aren’t used routinely. For now, egg quality is judged mainly by its appearance and how well it fertilises and develops into an embryo — a reminder that “quality” is about potential, not perfection. [33]

Can low ovarian response signal poor egg quality?

Not always — a low ovarian response usually means fewer eggs, not necessarily poorer quality. Research shows that women under 35 who produce fewer eggs during IVF can still have healthy, normal-looking eggs and embryos. However, with fewer eggs collected, the overall chances of fertilisation and implantation are lower. In older women, low response is more likely to reflect both reduced egg quantity and quality, since egg health naturally declines with age. [20,34,35]

Sources

  1. Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Eggs.
  2. Keefe, D., Kumar, M. and Kalmbach, K., 2015. Oocyte competency is the key to embryo potential. Fertility and Sterility, 103(2), pp.317-322.
  3. Thomas C, Cavazza T, Schuh M. Aneuploidy in human eggs: contributions of the meiotic spindle. Biochem Soc Trans. 2021 Feb 26;49(1):107-118. doi: 10.1042/BST20200043. PMID: 33449109; PMCID: PMC7925012.
  4. Chappel S. The role of mitochondria from mature oocyte to viable blastocyst. Obstet Gynecol Int. 2013;2013:183024. doi: 10.1155/2013/183024. Epub 2013 May 16. PMID: 23766762; PMCID: PMC3671549.
  5. Haseeb, M.A., Weng, K.A. and Bickel, S.E., 2024. Chromatin-associated cohesin turns over extensively and forms new cohesive linkages in Drosophila oocytes during meiotic prophase. Current Biology, 34(13), pp.2868-2879.
  6. Kalmbach KH, Fontes Antunes DM, Dracxler RC, Knier TW, Seth-Smith ML, Wang F, Liu L, Keefe DL. Telomeres and human reproduction. Fertil Steril. 2013 Jan;99(1):23-29. doi: 10.1016/j.fertnstert.2012.11.039. PMID: 23273986; PMCID: PMC3857638.
  7. Disler, E.R., Ng, N.W., Nguyen, T.G., Anchan, C.J., Waldman, I.N. and Anchan, R.M., 2021. Induced pluripotent stem cell derived from ovarian tissue. In Cell Sources for iPSCs (pp. 107-135). Academic Press.
  8. Owen A, Carlson K, Sparzak PB. Age-Related Fertility Decline. Updated 2024 Feb 2.
  9. Hassold T, Hunt P. Maternal age and chromosomally abnormal pregnancies: what we know and what we wish we knew. Curr Opin Pediatr. 2009 Dec;21(6):703-8. doi: 10.1097/MOP.0b013e328332c6ab. PMID: 19881348; PMCID: PMC2894811.
  10. Al-Saleh I, Coskun S, Al-Rouqi R, Al-Rajudi T, Eltabache C, Abduljabbar M, Al-Hassan S. Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment. Reprod Fertil. 2021 May 18;2(2):117-139. doi: 10.1530/RAF-20-0062. PMID: 35128448; PMCID: PMC8812407.
  11. Ruder EH, Hartman TJ, Goldman MB. Impact of oxidative stress on female fertility. Curr Opin Obstet Gynecol. 2009 Jun;21(3):219-22. doi: 10.1097/gco.0b013e32832924ba. PMID: 19469044; PMCID: PMC2749720.
  12. Zaha I, Muresan M, Tulcan C, Huniadi A, Naghi P, Sandor M, Tripon R, Gaspar C, Klaudia-Melinda M, Sachelarie L, Stefan L. The Role of Oxidative Stress in Infertility. J Pers Med. 2023 Aug 15;13(8):1264. doi: 10.3390/jpm13081264. PMID: 37623514; PMCID: PMC10455473.
  13. Latif S, Saridogan E. Endometriosis, Oocyte, and Embryo Quality. J Clin Med. 2023 Jun 21;12(13):4186. doi: 10.3390/jcm12134186. PMID: 37445220; PMCID: PMC10342681.
  14. Sanchez AM, Vanni VS, Bartiromo L, Papaleo E, Zilberberg E, Candiani M, Orvieto R, Viganò P. Is the oocyte quality affected by endometriosis? A review of the literature. J Ovarian Res. 2017 Jul 12;10(1):43. doi: 10.1186/s13048-017-0341-4. PMID: 28701212; PMCID: PMC5508680.
  15. Jain M, Carlson K, Singh M. Environmental Toxins and Infertility. Updated 2025 Jan 19.
  16. NHS East and North Hertfordshire, NHS Trust. Date of publication: January 2016.
  17. Nikbakht R, Mohammadjafari R, Rajabalipour M, Moghadam MT. Evaluation of oocyte quality in Polycystic ovary syndrome patients undergoing ART cycles. Fertil Res Pract. 2021 Jan 5;7(1):2. doi: 10.1186/s40738-020-00094-z. PMID: 33397466; PMCID: PMC7784377.
  18. NHS. Polycystic ovary syndrome. Page last reviewed: 11 October 2022.
  19. Prasad S, Tiwari M, Pandey AN, Shrivastav TG, Chaube SK. Impact of stress on oocyte quality and reproductive outcome. J Biomed Sci. 2016 Mar 29;23:36. doi: 10.1186/s12929-016-0253-4. PMID: 27026099; PMCID: PMC4812655.
  20. NHS. Infertility. Page last reviewed: 09 August 2023.
  21. Navot D, Bergh PA, Williams MA, Garrisi GJ, Guzman I, Sandler B, Grunfeld L. Poor oocyte quality rather than implantation failure as a cause of age-related decline in female fertility. Lancet. 1991 Jun 8;337(8754):1375-7. doi: 10.1016/0140-6736(91)93060-m. PMID: 1674764.
  22. NHS South Tees Hospitals. NHS Foundation Trust. Follicle stimulating hormone (FSH). Page last updated: 27/04/2022.
  23. NHS. Trying to get pregnant. Page last reviewed: 14 November 2023.
  24. NHS Inform. Planning for pregnancy. 02 July 2025.
  25. Tommy’s. The benefits of exercising/being active when trying to conceive. Reviewed: 29 August 2023.
  26. Human Fertilisation & Embryology Authority. Androgen supplementation.
  27. Sood A, Mohiyiddeen G, Ahmad G, Fitzgerald C, Watson A, Mohiyiddeen L. Growth hormone for in vitro fertilisation (IVF). Cochrane Database Syst Rev. 2021 Nov 22;11(11):CD000099. doi: 10.1002/14651858.CD000099.pub4. PMID: 34808697; PMCID: PMC8608438.
  28. NHS. Planning your pregnancy. Page last reviewed: 26 April 2023.
  29. NHS The Newcastle upon Tyne Hospitals, NHS Foundation Trust. Preparation for pregnancy. Page last updated: 08/11/2022.
  30. Rodríguez-Varela C, Labarta E. Does Coenzyme Q10 Supplementation Improve Human Oocyte Quality? Int J Mol Sci. 2021 Sep 2;22(17):9541. doi: 10.3390/ijms22179541. PMID: 34502447; PMCID: PMC8431086.
  31. Human Fertilisation & Embryology Authority Dashboard.
  32. Human Fertilisation & Embryology Authority. What you need to know about our new egg freezing report. Publication date: 15 April 2025.
  33. Moghadam ARE, Moghadam MT, Hemadi M, Saki G. Oocyte quality and aging. JBRA Assist Reprod. 2022 Jan 17;26(1):105-122. doi: 10.5935/1518-0557.20210026. PMID: 34338482; PMCID: PMC8769179.
  34. Nichi M, de Cassia Sávio Figueira R, Paes de Almeida Ferreira Braga D, Souza Setti A, Iaconelli A Jr, Borges E Jr. Decreased fertility in poor responder women is not related to oocyte morphological status. Arch Med Sci. 2011 Apr;7(2):315-20. doi: 10.5114/aoms.2011.22084. Epub 2011 May 17. PMID: 22291773; PMCID: PMC3258723.
  35. Bahadur G, Homburg R, Jayaprakasan K, Raperport CJ, Huirne JAF, Acharya S, Racich P, Ahmed A, Gudi A, Govind A, Jauniaux E. Correlation of IVF outcomes and number of oocytes retrieved: a UK retrospective longitudinal observational study of 172 341 non-donor cycles. BMJ Open. 2023 Jan 2;13(1):e064711. doi: 10.1136/bmjopen-2022-064711. PMID: 36592998; PMCID: PMC9809223.