Poor Egg Quality: Defining and Investigating
Egg quality is central—and arguably the most important variable—in both natural and assisted human reproduction.
It is vital to understand that poor egg quality is an observation, not a diagnosis. It is a conclusion typically reached by an embryologist noting poor embryo cleavage, often starting the day after fertilization, or gross chromosomal errors across all blastocysts. While eggs may occasionally display visual abnormalities, these cases are uncommon and the visual signs are, in the vast majority of cases, highly irrelevant. Nonetheless, these visual markers are frequently inappropriately treated as definitive signs of poor egg quality and blamed for poor embryo development.
Beyond the Laboratory: The History of the Egg
Until 2020, the approach to egg quality was largely empirical and, frankly, fatalistic. Poor egg quality was rarely properly recognized as a manageable physiological state. Instead, poor embryo development was often erroneously attributed to laboratory errors, without regard for the egg’s history before reaching the embryologist.
Despite the wide acceptance of the fact that egg quality decreases with age, the field was slow to recognize that quality is the totality of an egg’s history—a history that can be influenced. Historically, few publications pointed to the impact of the patient’s history during the critical last two weeks of development: the follicular phase. Existing research often focused narrowly on the potential harm of high FSH or compared different protocols in a purely empirical fashion.
The Dozortsev-Diamond Paradigm: A Foundation for Rational Practice
The entire field has historically moved forward empirically, but this was not the fault of practitioners. The problem existed at a deeper layer: a major error in the understanding of reproductive physiology—the “holy grail” of the reproductive cycle, ovulation. This created a “Ruben sandwich” of errors that prevented translational fertility from serving as a foundation for rational practice.
These errors began to unravel with the introduction of the Dozortsev-Diamond Ovulation Paradigm. This paradigm identifies the true trigger of the LH surge and the “Safe-Fail” mechanics of the ovarian cortex, providing a scientific framework to replace outdated 1970s models.
This site is dedicated to revising the basics of reproductive physiology within the context of the Dozortsev-Diamond paradigm. While this shift has many ramifications for the understanding and management of infertility, its impact on egg quality is the most consequential. Therefore, this site is first and foremost about the science of egg quality.
What is Poor Egg Quality?
The term “poor egg quality” is, in many ways, a misnomer. It implies an inherent, fixed, and irreversible defect in a woman’s oocytes. In reality, the situation is far more nuanced. Egg quality is not a binary condition but a dynamic expression of physiology, influenced by timing, hormonal environment, ovarian function, and the clinical context in which the egg develops and is evaluated.
Not a Diagnosis, But an Observation
First and foremost, poor egg quality is not a formal medical diagnosis. Rather, it is an observation based on the outcomes of an In Vitro fertilization (IVF) cycle. An embryologist or physician may describe egg quality as “poor” when a cohort of retrieved oocytes fails to fertilize, develop into viable embryos, or results in a high rate of chromosomally abnormal blastocysts.
Fertilization Failures: A low rate of fertilization despite good sperm parameters can be an indicator.
Embryo Arrest: A common pattern of poor egg quality is normal fertilization followed by failure of the embryos to develop in vitro to the blastocyst stage (day 5-7 of development) and instead becoming arrested (stop developing) on day 2-4 of development.
High Rates of Aneuploidy: Embryos may develop to the blastocysts, but Preimplantation Genetic Testing (PGT-A) reveals that all of them are chromosomally abnormal.
Visual abnormalities of the eggs: This is the least common. Sometimes an embryologist will note that eggs before fertilization do not look as would be expected. In most cases there are no reliable visual clues, despite any claims to the contrary, that would predict oocyte quality. We know this, because we commonly see what would be called visual abnormalities in egg donors and their eggs develop perfectly fine.
As you can see, these are descriptions of an outcome, not a prospective prediction of every egg’s potential. Think of it less as a definitive statement about future fertility potential and more as a single data point that requires deeper investigation.
Egg Quality Distribution
It is understood that every woman, regardless of her age or health status, has a mixture of good and poor quality eggs in her ovaries. Indeed, a healthy woman in her twenties will still have a significant percentage of poor quality oocytes. The difference is that she has a much larger pool of better quality eggs to draw from, making the probability of recruiting a healthy oocyte in any given cycle higher and her follicular phase duration is usually more close to term. Therefore, observing poor quality eggs does not mean all eggs are of poor quality; it may reflect the specific cohort of follicles that were recruited and stimulated in that particular cycle or otherwise normal egg quality has deteriorated in response to addition of reproductive hormones or other medications used during ovarian stimulation, duration of ovarian stimulation or problems with ovarian tissues.
Causes of Poor Egg Quality
Most current theories regarding poor egg quality are either too generalized or too speculative to be clinically useful. While numerous supplements, vitamins, and lifestyle changes are marketed as solutions, conclusive evidence of their benefit remains rare. Objectivity in this area is often compromised, as many studies are sponsored by entities with a financial interest in the outcome.
On the other hand, while basic science may identify specific cellular changes—such as reduced mitochondrial activity in vitro—these findings often lack a clinical “entry point.” For example, if an egg shows reduced mitochondrial function in a lab setting, there is currently no proven in vivo medication to reverse this for the patient. Similarly, while “hormonal imbalance” is frequently cited as a cause, there is rarely a precise definition of which specific imbalances are at play or how to correct them.
A Translational Framework for Egg Quality
Emerging evidence suggests that specific hormonal imbalances, ovarian tissue factors, and inflammatory markers directly impact the follicle during its most critical phase: the final two weeks of development. Because this window is accessible to clinical intervention, we can strategically influence egg quality by addressing the following:
Endocrine Environment: LH and FSH levels directly impact oocyte maturation, while Estradiol and Progesterone serve as critical biomarkers of the egg’s developmental trajectory.
Follicular Phase Duration: A follicular phase that is either accelerated or excessively prolonged can significantly compromise egg quality.
The Ovarian Cortex: The physical and biochemical properties of the ovarian cortex determine length of the follicular phase. It ends when cortex can no longer accommodate the expansion of the follicle without losing its integrity.
Inflammation: Inflammatory factors, interacting with the ovarian cortex, act as key determinants of the duration of follicular phase.
The Diagnostic Cycle
A rational approach to managing poor egg quality must move beyond trial and error. Before attempting a new IVF cycle, it is essential to conduct a diagnostic cycle. This allows for a granular, patient-specific understanding of reproductive physiology, ensuring that subsequent treatments are tailored to the individual’s unique hormonal and ovarian profile.
Miscellaneous comments
Endometriosis:
There are multiple lines of evidence linking endometriosis to poor egg quality, and yet the connection has never been conclusively proven. Since about 20% many of females have some form of endometriosis, it has become a convenient explanation for a connection that may not, in fact, be causative. In one study, which in my opinion is most valuable because it is unbiased, it was demonstrated that a random finding of endometriosis has no correlation with fertility whatsoever.
https://obgyn.onlinelibrary.wiley.com/doi/10.3109/00016348709022053
Diminished Ovarian Reserve (DOR):
By itself, diminished ovarian reserve (fewer follicles seen on ultrasound at the start of the cycle or low AMH) is not predictive of egg quality. Also, in general, the number of follicles and their quality are not causatively linked. But with the percentage of good quality eggs being equal, clearly a female with more follicles will have a better chance of pregnancy. Even though the number of follicles in the ovaries is unidirectionally decreasing, and AMH has a similar overall trend, the number of follicles seen on ultrasound at the start of the cycle and FSH can vary widely from cycle to cycle. Sometimes it is worthwhile to wait for a larger wave of follicles before starting stimulation, and sometimes a better pool of follicles is formed after ovulation than at the start of the cycle. Shifting the frame of the stimulation to catch that wave can be beneficial.
Autoimmune Conditions
Current evidence linking autoimmunity per se to impaired oocyte quality is indirect and remains speculative. The most robust data in women with autoimmune disease relate to ovarian reserve/premature ovarian insufficiency, where causality is multifactorial and difficult to separate from disease severity and treatment effects. In contrast, the gonadotoxic impact of certain medications used to treat autoimmunity—particularly alkylating agents such as cyclophosphamide—on ovarian reserve is well documented, and in many patients likely represents the dominant iatrogenic risk to egg quality and quantity.
Environmental and Lifestyle Factors
While there is much speculation about the impact of lifestyle on egg quality, the scientific evidence for a direct causative link is often not as strong as is commonly believed.
The impact of oxidative stress, toxins, and chronic inflammation on egg quality is speculative. There are no epidemiological evidences that people living in deplorable conditions are less fertile. The same is applicable to chronic inflammation, which may indirectly affect natural fertility by handicap, but there is no direct causative connection to egg quality.
Elevated FSH and Low AMH
Elevated FSH levels and low AMH are predictive of a fewer number of follicles at the start of the cycle, but they are not related to egg quality. A female with a low AMH, for example 0.1, may be perfectly fertile and will be surprised to find out that her AMH is so low. Even though low AMH and high FSH may predict impending or early menopause, they are not predictive of poor egg quality.
Abnormal Estradiol Patterns:
Estradiol varies widely and its level has very small clinical significance.
Premature Progesterone Elevation:
A premature rise of progesterone during the natural follicular phase, for example on day 10 of the cycle, indicates issues with the follicle, ovarian cortex, or the level of FSH. Its premature rise will produce a shorter follicular phase, which is associated with lower egg quality. But in this case, it is not necessarily intrinsic but caused by factors outside of the egg and can occur at any age. A premature rise of progesterone during ovarian stimulation, as long as LH is well suppressed, is usually not consequential for all eggs’ quality, except for the single egg inside of the follicle which luteinizes prematurely and is responsible for the elevated progesterone.
Elevated LH:
LH elevation above 5 IU/L any time during the follicular phase can have a negative influence on otherwise healthy oocytes, decreasing their quality.
Dietary Interventions
There are many opinions and inconclusive research but no real scientific evidence that any dietary changes affect fertility. The only exception is some types of insulin resistance, but even then it is not clear whether it is causing ovulation problems or simply occurs concurrently with reproductive hormone imbalances. Even if it were true that insulin resistance directly affects ovulation, there is no proven connection with egg quality.
Supplements
Many supplements are marketed for improving egg quality. However, the evidence is often not as strong as the claims.
Unless some proven deficiency known to affect egg quality exists (and I am not sure what that would be), it is not possible to improve it with supplements.
- Coenzyme Q10 (CoQ10): Proposed to support mitochondrial function. Some studies have suggested a potential benefit, but the connection to egg quality is not definitively proven.
- Myo-Inositol and D-Chiro-Inositol: Often recommended for women with PCOS to improve insulin sensitivity. While it may help regulate cycles in this population, a direct link to improved oocyte quality is speculative.
- Vitamin D, Folate, Omega-3s, NAC, ALA, Melatonin, DHEA, Resveratrol:
For these and many other supplements, there are a lot of publications, speculations, and ideas, but no proven connection to egg quality. While some, like folate, are essential for pregnancy to prevent neural tube defects, their role in improving the intrinsic quality of the oocyte is not established.