Why Did So Few of My Eggs Fertilize and Make it to Blastocyst?

One of the commonest questions asked by patients undergoing IVF relates to the likelihood of their eggs fertilizing and the likely “quality of their embryos. This is also one of the most difficult questions to answer. On the one hand many factors that profoundly influence egg quality; such as the genetic recruitment of eggs for use in an upcoming cycle, the woman’s age and her ovarian reserve, are our outside of our control. On the other hand the protocol for controlled ovarian stimulation (COS) can also profoundly influence egg/embryo development and this is indeed chosen by the treating physician.

First; it should be understood that the most important determinant of fertilization potential, embryo development and blastocyst generation, is the numerical chromosomal integrity of the egg (While sperm quality does play a role, in the absence of moderate to severe sperm dysfunction this is (moderate or severe male factor infertility a relatively small one). Human eggs have the highest rate of numerical chromosomal irregularities (aneuploidy) of all mammals. In fact only about half the eggs of women in their twenties or early thirties, have the required number of chromosomes (euploid), without which upon fertilization the cannot propagate a normal pregnancy. As the woman advances into and beyond her mid-thirties, the percentage of eggs euploid eggs declines progressively such that by the age of 40 years, only about one out of seven or eight are likely to be chromosomally normal and by the time she reaches her mid-forties less than one in ten of her eggs will be euploid.

Second; embryos that fail to develop into blastocysts are almost always aneuploid and not worthy of being transferred to the uterus because they will either not implant, will miscarry or could even result in a chromosomally abnormal baby (e.g. Down syndrome). However, it is incorrect to assume that all embryos reaching the blastocyst stage will be euploid (“competent”).  ). It is true that since many aneuploid embryos are lost during development and that those failing to survive to the blastocyst stage are far more likely to be competent than are earlier (cleaved) embryos.  What is also true is that the older the woman who produces the eggs, the less likely it is that a given blastocyst will be “competent”. As an example, a morphologically pristine blastocyst derived from the egg of a 30-year-old woman would have about a 50:50 chance of being euploid and a 30% chance of propagating a healthy, normal baby, while a microscopically comparable blastocyst-derived through fertilization of the eggs from a 40-year-old, would be about half as likely to be euploid and/or propagate a healthy baby.

While the effect of species on the potential of eggs to be euploid at ovulation is genetically preordained and nothing we do can alter this equation, there is, unfortunately, a lot we can (often unwittingly) do to worsen the situation by selecting a suboptimal protocol of controlled ovarian stimulation (COS). This, by creating an adverse intraovarian hormonal environment will often disrupt normal egg development and lead to a higher incidence of egg aneuploidy than otherwise might have occurred.  Older women, women with diminished ovarian reserve (DOR) and those with polycystic ovarian syndrome are especially vulnerable in this regard.

During the normal, ovulation cycle, ovarian hormonal changes are regulated to avoid irregularities in production and interaction that could adversely influence follicle development and egg quality. As an example, small amounts of androgens (male hormones such as testosterone), that are produced by the ovarian stroma (tissue surrounding ovarian follicles) during the pre-ovulatory phase of the cycle enhance late follicle development, estrogen production by the granulosa cells (that line the inner walls of follicles), and egg maturation. However, over-production of testosterone can adversely influence the same processes. It follows that COS protocols should be individualized and geared toward optimizing follicle growth and development time while avoiding excessive ovarian androgen (testosterone) production and that the hCG “trigger shot” should be carefully timed.

In summary, it is important to understand the influence species, age of the woman as well as the effect of the COS protocol can have on egg/embryo quality and thus on IVF outcome. The selection of an individualized protocol for ovarian stimulation is one of the most important decisions that the RE has to make and this becomes even more relevant when dealing with older women, those with DOR and women with PCOS. Such factors will in large part determine fertilization potential, the rate of blastocyst generation and indeed IVF outcome.


alicia martinez

Dear Dr Sher,

Would you rather recommend GnRH agonist trigger versus hCG trigger for an older woman suffering from stage 3 endometriosis with DOR? Following COS with FSH injections, follicles seem to grow normally, however upon retrieval most MII eggs are poor quality. Ive done 5 ERs with Ovitrelle and my RE wants to try something different.

thank you,

Dr. Geoffrey Sher

Respectfully, I would absolutely NOT so recommend!

Some IVF physicians advocate the use of GnRHa (Lupron)- flare protocols in which the administration of Lupron, therapy begins at the same time that ovarian stimulation with gonadotropins is started (usually with the onset of menstruation). The proposed benefit of such an approach is that the GnRHa will cause the woman’s pituitary gland to release large amounts of follicle stimulating hormone (FSH), which would augment the administered dosage of FSH and thereby synergizing the growth of ovarian follicles. The problem associated with this “flare” approach is that concurrent with the GnRHa-induced FSH luteinizing hormone (LH) also surges. In older women and those who have diminished ovarian reserve, the out-pouring of LH can cause the ovarian connective tissue (stroma or theca) which produces excessive male hormones (predominantly, testosterone). While some testosterone is essential for optimal follicle growth, too much testosterone can compromise its development as well as egg/embryo quality. Since older women and women with diminished ovarian reserve often have increased LH production as well as an overgrown of ovarian stroma/theca (i.e. hyperthecosis), a further GnRHa-induced increase in LH can so elevate local ovarian testosterone levels as to severely compromise egg/ embryo “competency”.

Women who (regardless of age) have diminished ovarian reserve (DOR) have a reduced potential for IVF success. Much of this is due to the fact that such women tend to have increased production, and/or biological activity, of LH. This can result in excessive ovarian male hormone (predominantly testosterone) production. This in turn can have a deleterious effect on egg/embryo “competency”.
While it is presently not possible by any means, to reverse the effect of DOR, certain ovarian stimulation regimes, by promoting excessive LH production (e.g. short agonist/Lupron- “flare” protocols, clomiphene and Letrozole), can in my opinion, make matters worse. Similarly, the amount/dosage of certain fertility drugs that contain LH/hCG (e.g. Menopur) can have a negative effect on the development of the eggs of older women and those who have DOR and should be limited.
I try to avoid using such protocols/regimes (especially) in women with DOR, favoring instead the use of the agonist/antagonist conversion protocol (A/ACP), a modified, long pituitary down-regulation regime, augmented by adding supplementary human growth hormone (HGH). I further recommend that such women be offered access to embryo banking of PGS (next generation gene sequencing/NGS)-selected normal blastocysts, the subsequent selective transfer of which by allowing them to capitalize on whatever residual ovarian reserve and egg quality might still exist and thereby “make hay while the sun still shines” could significantly enhance the opportunity to achieve a viable pregnancy
Please visit my new Blog on this very site, www. SherIVF.com, find the “search bar” and type in the titles of any/all of the articles listed below, one by one. “Click” and you will immediately be taken to those you select. Please also take the time to post any questions or comments with the full expectation that I will (as always) respond promptly

• Controlled Ovarian Stimulation (COS) for IVF: Selecting the ideal protocol
• IVF: Factors Affecting Egg/Embryo “competency” during Controlled Ovarian Stimulation(COS)
• The Fundamental Requirements For Achieving Optimal IVF Success
• Ovarian Stimulation for IVF using GnRH Antagonists: Comparing the Agonist/Antagonist Conversion Protocol.(A/ACP) With the “Conventional” Antagonist Approach
• Anti Mullerian Hormone (AMH) Measurement to Assess Ovarian Reserve and Design the Optimal Protocol for Controlled Ovarian Stimulation (COS) in IVF.
• The “Biological Clock” and how it should Influence the Selection and Design of Ovarian Stimulation Protocols for IVF.
• A Rational Basis for selecting Controlled Ovarian Stimulation (COS) protocols in women with Diminished Ovarian Reserve (DOR)
• Diagnosing and Treating Infertility due to Diminished Ovarian Reserve (DOR)
• Controlled Ovarian Stimulation (COS) in Older women and Women who have Diminished Ovarian Reserve (DOR): A Rational Basis for Selecting a Stimulation Protocol
• Human Growth Hormone Administration in IVF: Does it Enhances Egg/Embryo Quality and Outcome?
• The BCP: Does Launching a Cycle of Controlled Ovarian Stimulation (COS). Coming off the BCP Compromise Response?
• Blastocyst Embryo Transfers Should be the Standard of Care in IVF
• Frozen Embryo Transfer (FET) versus “Fresh” ET: How to Make the Decision
• Frozen Embryo Transfer (FET): A Rational Approach to Hormonal Preparation and How new Methodology is Impacting IVF.
• Staggered IVF: An Excellent Option When. Advancing Age and Diminished Ovarian Reserve (DOR) Reduces IVF Success Rate
• Embryo Banking/Stockpiling: Slows the “Biological Clock” and offers a Selective Alternative to IVF-Egg Donation.
• Preimplantation Genetic Testing (PGS) in IVF: It Should be Used Selectively and NOT be Routine.
• Preimplantation Genetic Sampling (PGS) Using: Next Generation Gene Sequencing (NGS): Method of Choice.
• PGS in IVF: Are Some Chromosomally Abnormal Embryos Capable of Resulting in Normal Babies and Being Wrongly Discarded?
• PGS and Assessment of Egg/Embryo “competency”: How Method, Timing and Methodology Could Affect Reliability
• Treating Out-of-State and Out-of-Country Patients at Sher-IVF in Las Vegas:
• Traveling for IVF from Out of State/Country–
• A personalized, stepwise approach to IVF
• How Many Embryos should be transferred: A Critical Decision in IVF.
• The Role of Nutritional Supplements in Preparing for IVF
• Premature Luteinization (“the premature LH surge): Why it happens and how it can be prevented.
• IVF Egg Donation: A Comprehensive Overview

Founded in April 2019, Sher Fertility Solutions (SFS) offers online (Skype/FaceTime) consultations to patients from > 40 different countries. All consultations are followed by a detailed written report presenting my personal recommendations for treatment of what often constitute complex Reproductive Issues.

If you wish to schedule an online consultation with me, please contact my assistant (Patti Converse) by phone (800-780-7437/702-533-2691), email (concierge@SherIVF.com) or, enroll online on then home-page of my website (www.SherIVF.com).


Geoff Sher

Geoff Sher


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