The journey of in vitro fertilization can be a rollercoaster of emotions for many patients. Often times they have to face the harsh reality that the number and quality of eggs retrieved has fallen short of their expectations. Then, should fertilization of these eggs not propagate chromosomally normal (euploid), “competent” embryos suitable for transfer to the uterus, many such patients find themselves in a state of emotional distress. They grapple with the inevitable questions of why this happened and how to prevent it from occurring again in the future. This article aims to delve into these queries, providing insights, rational explanations, and therapeutic options. It is an invitation to explore the light at the end of the tunnel. Readers are urged to carefully absorb the entirety of the article in the hope of finding valuable information and renewed hope.
- The Importance of Chromosomal Integrity: While sperm quality is an important factor, egg quality is by far the most important when it comes to the generation of embryos that are capable of propagating healthy babies (“competent”). In this regard, chromosomal integrity of the egg and embryo, although it is not the only factor, is certainly the main determinant of such competency.
- The woman’s age: About two thirds of a woman’s eggs in her twenties or early thirties have the correct number of chromosomes, which is necessary for a healthy pregnancy. As a woman gets older, the percentage of eggs with the right number of chromosomes decreases. By age 40, only about one in every 5-6 eggs is likely to be normal, and by the mid-forties, less than one in ten eggs will be normal.
- Ovarian Reserve (number of available in the ovaries): A woman is born with all the eggs she will ever have. She starts using these eggs when she begins ovulating during puberty. At first, the eggs are used up quickly, but as she gets older, the number of eggs starts to run out. Her brain and pituitary gland try to stimulate the production of more eggs by increasing the output of Follicle Stimulating Hormone (FSH), but unfortunately, this often doesn’t work. When the number of remaining eggs in her ovaries falls below a certain level (which can be different for each woman), her FSH level rises, and production of the ovarian hormone, AMH decreases. This is the start of diminishing ovarian reserve (DOR). Most women experience the onset of DOR in their late 30s or early 40s, but it can happen earlier for some. The lower the ovarian reserve, the lower the AMH level will be, and the fewer eggs will be available for harvesting during IVF-egg retrieval. In such cases, a higher dosage of fertility drugs might be needed to promote better egg production in future attempts. On the other hand, higher AMH levels mean more eggs are available, and lower doses of fertility drugs are usually needed. DOR is commonly associated with increased bioactivity of pituitary gland-produced LH. This LH activates production of ovarian male hormones (androgens)…predominantly testosterone by ovarian connective tissue (stroma). While a small amount of ovarian testosterone is absolutely necessary for optimal follicle and egg development, excessive ovarian testosterone will often access the follicle, and compromise both egg quality and follicle growth and development. In some cases, rapidly increasing LH-release (“premature LH-surge”) with excessive induced ovarian testosterone can lead to “premature luteinization” of the follicles with cessation in growth and even to “premature ovulation”.
- Importance of Individualized Controlled Ovarian Stimulation (COS) Protocol: It’s not surprising that DOR is more common in older women, but regardless of age, having DOR makes a woman’s eggs more likely to be compromised during controlled ovarian stimulation (COS). The choice of the COS protocol is crucial to preventing unintentional harm to egg and embryo quality. The wrong protocol can disrupt normal egg development and increase the risk of abnormal embryos. That’s why it’s important to tailor the COS protocol to each individual’s needs. This helps optimize follicle growth and the quality of eggs and embryos. The timing of certain treatments is also important for successful outcomes.
- Embryo Competency and Blastocyst Development: Embryos that don’t develop into blastocysts by day 6 after fertilization are usually chromosomally abnormal or aneuploid (”incompetent”) and not suitable for transfer. However, not all blastocysts are guaranteed to be normal and capable of developing into a healthy baby. As a woman gets older, the chances of her embryos being chromosomally normal blastocyst decreases. For example, a blastocyst from a 30-year-old woman is more likely to be normal compared to one from a 40-year-old woman.
The IVF stimulation protocol has a big impact on the quality of eggs and embryos especially in women with DOR. Unfortunately, many IVF doctors use the same COS “recipe approach” for everyone without considering individual differences. Using personalized protocols can greatly improve the success of IVF. While we can’t change genetics or reverse a woman’s age, a skilled IVF specialist can customize the COS protocol to meet each patient’s specific needs.
GONADOTROPIN RELEASING HORMONE AGONISTS (GNRHA) AND GNRH-ANTAGONISTS:
- Gonadotropin releasing hormone agonists (GnRHa). Examples are Lupron, Buserelin, Superfact, and Decapeptyl. These are commonly used to launch ovarian stimulation cycles. They work by initially causing a release of pituitary gonadotropins, followed by a decrease in LH and FSH levels within 4-7 days. This creates a relatively low LH environment when COS begins, which is generally beneficial for egg development. However, if GnRHa are administered starting concomitant with gonadotropin stimulation (see GnRHa – “flare protocol” -below) it can cause an immediate surge in LH release, potentially leading to high levels of ovarian testosterone that can harm egg quality, especially in older women and those with diminished ovarian reserve (DOR).
- Gonadotropin releasing hormone antagonists (GnRH-antagonists): Examples are Ganirelix, Cetrotide, and Orgalutron. GnRH antagonists (take days work quickly (within hours) to block pituitary LH release. Their purpose is to prevent excessive LH release during COS. In contrast, the LH-lowering effect of GnRH agonists takes several days to develop. Traditionally, GnRH antagonists are given starting on the 5th-7th day of gonadotropin stimulation. However, in older women and those with DOR, suppressing LH might happen too late to prevent excessive ovarian androgen production that can negatively impact egg development in the early stages of stimulation. That’s why I prefer to administer GnRH-antagonists right from the beginning of gonadotropin administration.
USING BIRTH CONTROL PILLS TO START OVARIAN STIMULATION:
Patients are often told that using birth control pills (BCP) to begin ovarian stimulation will suppress the response of the ovaries. This is true, but only if the BCP is not used correctly. Here’s the explanation:
In natural menstrual cycles and cycles stimulated with fertility drugs, the follicles in the ovaries need to develop receptors that respond to follicle-stimulating hormone (FSH) in order to properly respond to FSH stimulation. Pre-antral follicles (PAFs) do not have these receptors and cannot respond to FSH stimulation. The development of FSH responsivity requires exposure of the pre-antral follicles to FSH for several days, during which they become antral follicles (AFs) and gain the ability to respond to FSH-gonadotropin stimulation. In regular menstrual cycles, the rising FSH levels naturally convert PAFs to AFs. However, the combined BCP suppresses FSH. To counter this suppression, we need to promote increased FSH production several days before starting COS. This allows the orderly conversion from PAFs to AFs, ensuring proper follicle and egg development.
GnRHa causes an immediate surge in FSH release by the pituitary gland, promoting the conversion from PAF to AF. Therefore, when women take the BCP control pill to launch a cycle of COS, they need to overlap the BCP with a GnRHa for a few days before menstruation. This allows the early recruited PAFs to complete their development and reach the AF stage, so they can respond appropriately to ovarian stimulation. By adjusting the length of time, the woman is on the birth control pill, we can regulate and control the timing of the IVF treatment cycle. Without this step, initiating ovarian stimulation in women coming off birth control pills would be suboptimal.
PROTOCOLS FOR CONTROLLED OVARIAN STIMULATION (COS):
- GnRH Agonist Ovarian Stimulation Protocols:
- The long GnRHa protocol: Here, a GnRHa (usually Lupron or Superfact) is given either in a natural cycle, starting 5-7 days before menstruation, overlapping with the BCP for three days. Thereupon, the pill is stopped, while daily GnRHa injections continue until menstruation occurs (usually 5-7 days later). The GnRHa causes a rapid rise in FSH and LH levels. This is followed about 3-4 days later, by a progressive decline in FSH and LH to near zero levels, with a concomitant drop in ovarian estradiol and progesterone. This, in turn triggers uterine withdrawal bleeding (menstruation) within 5-7 days of starting the GnRHa administration. Gonadotropin treatment is then initiated while daily GnRHa injections continue to maintain a relatively low LH environment. Gonadotropin administration continues until the hCG “trigger” (see below).
- Short GnRH-Agonist (“Flare”) Protocol: This protocol involves starting hormone therapy and using GnRH agonist at the same time. The goal is to boost FSH so that with concomitant stimulation with FSH-gonadotropins + the GnRHa-induced surge in pituitary gland FSH release, will augment follicle development. However, this surge also leads to a rise in LH levels, which can cause an excessive production of ovarian male hormones (e.g., testosterone). This could potentially adversely affect the quality of eggs, especially in women over 39 years old, those with low ovarian reserve, and women with PCOS or DOR who already have increased LH sensitivity. In this way, these “flare protocols” can potentially decrease the success rates of IVF. While they are generally safe for younger women with normal ovarian reserve, I personally avoid using this approach on the off chance that even patients with normal ovarian reserve, might experience poor egg quality.
- GnRH Antagonist-Ovarian Stimulation Protocols:
- Conventional GnRH Antagonist Protocol: In this approach, daily GnRH antagonist injections are given from the 5th to the 8th day of COS with gonadotropins to the day of the “trigger” (see below). Accordingly, although rapidly acting to lower LH, this effect of GnRH- antagonist only starts suppressing LH from well into the COS cycle which means the ovarian follicles are left exposed and unshielded from pituitary gland -produced, (endogenous) LH during the first several days of stimulation. This can be harmful, especially in the early stage of COS when eggs and follicles are most vulnerable to the effects of over-produced LH-induced excessive ovarian testosterone. Therefore, I believe the Conventional GnRH Antagonist Protocol is not ideal for older women, those with low ovarian reserve, and women with PCOS who already have elevated LH activity. However, this protocol is acceptable for younger women with normal ovarian reserve, although I personally avoid using this approach on the off chance that even patients with normal ovarian reserve, might experience poor egg quality.
It’s important to note that the main reason for using GnRH antagonists is to prevent a premature LH surge, which is associated with poor egg and embryo quality due to follicular exhaustion. However, calling it a “premature LH surge” is misleading because it actually represents the culmination of a progressive increase in LH-induced ovarian testosterone. A better term would be “premature luteinization”. In some such cases, the rise in LH can precipitate “premature ovulation”.
- Agonist/Antagonist Conversion Protocol (A/ACP): I recommend this protocol for many of my patients, especially for older women and those with DOR or PCOS. The woman starts by taking a BCP for 7-10 days. This overlapped with a GnRHa for 3 days and continued until menstruation ensues about 5-7 days later. At this point she “converts” from the GnRH-agonist to a GnRH-antagonist (Ganirelix, Orgalutron, or Cetrotide). A few days after this conversion from agonist to antagonist, COS with gonadotropin stimulation starts. Both the antagonist and the gonadotropins are continued together until the hCG trigger. The purpose is to suppress endogenous LH release throughout the COS process and so avoid over-exposure of follicles and eggs to LH-induced excessive ovarian testosterone which as previously stated, can compromise egg and follicle growth and development. Excessive ovarian testosterone can also adversely affect estrogen-induced growth of the uterine lining (endometrium). Unlike GnRH-agonists, antagonists do not suppress ovarian response to the gonadotropin stimulation. This is why the A/ACP is well-suited for older women and those with diminished ovarian reserve.
- A/ACP with estrogen priming: This is a modified version of the A/ACP protocol used for women with very low ovarian reserve (AMH=<0.2ng/ml). Estrogen priming is believed to enhance the response of follicles to gonadotropins. Patients start their treatment cycle by taking a combined birth control pill (BCP) for 7-10 days. After that, they overlap daily administration of a GnRH agonist with the BCP for 3 days. The BCP is then stopped, and the daily agonist continues until menstruation ensues (usually 5-7 days later). At this point, the GnRH agonist is supplanted by daily injections of GnRH antagonist and Estradiol (E2) “priming” begins using E2 skin patches or intramuscular estradiol valerate injections twice weekly, while continuing the GnRH antagonist. Seven days after starting the estrogen priming COS begins using recombinant FSHr such as Follistim, Gonal-F or Puregon) +menotropin (e.g., Menopur). The estrogen “priming” continues to the day of the “trigger” (see below). Egg retrieval is performed 36 hours after the trigger.
Younger women (under 30 years) and women with absent, irregular, or dysfunctional ovulation, as well as those with polycystic ovarian syndrome (PCOS), are at risk of developing a severe condition called Ovarian Hyperstimulation Syndrome (OHSS), which can be life-threatening. To predict this condition, accurate daily blood E2 level monitoring is required.
TRIGGERING “EGG MATURATION PRIOR TO EGG RETRIEVAL”
- The hCG “trigger”: When it comes to helping eggs mature before retrieval, one of the important decisions the doctor needs to make is choosing the “trigger shot” to facilitate the process. Traditionally, hCG (human chorionic gonadotropin) is derived from the urine of pregnant women (hCGu) while a newer recombinant hCG (hCGr), Ovidrel was recently introduced. The ideal dosage of hCGu is 10,000U and for Ovidrel, the recommended dosage is 500mcg. Both have the same efficacy. The “trigger” is usually administered by intramuscular injection, 34-36 hours prior to egg retrieval.
Some doctors may choose to lower the dosage of hCG if there is a risk of severe ovarian hyperstimulation syndrome (OHSS). However, I believe that a low dose of hCG (e.g., 5000 units of hCGu or 250 mcg of hCGr (Ovidrel) might not be enough to optimize egg maturation, especially when there are many follicles. Instead, I suggest using a method called “prolonged coasting” to reduce the risk of OHSS.
- Using GnRH antagonist alone or combined with hCG as the trigger: Some doctors may prefer to use a GnRH- agonist trigger instead of hCG to reduce the risk of OHSS. The GnRHa “trigger” acts by inducing a “surge of pituitary gland-LH. However, it is difficult to predict the amount of LH that is released in response to a standard agonist trigger. In my opinion, using hCG is a better choice, even in cases of ovarian hyperstimulation, with the condition that “prolonged coasting” is implemented beforehand.
- Combined use of hCG + GnRH agonist: This approach is better than using a GnRH agonist alone but still not as effective as using the appropriate dosage of hCG.
- Timing of the trigger: The trigger shot should be given when the majority of ovarian follicles have reached a size of more than 15 mm, with several follicles measuring 18-22 mm. Follicles larger than 22 mm often contain overdeveloped eggs, while follicles smaller than 15 mm usually have underdeveloped and potentially abnormal eggs.
SEVERE OVARIAN HYPERSTIMULATION SYNDROME (OHSS) & “PROLONGED COASTING”
OHSS is a life-threatening condition that can occur during controlled ovarian stimulation (COS) when the blood E2 (estradiol) level rises too high. It is more common in young women with high ovarian reserve, women with polycystic ovarian syndrome (PCOS), and young women who do not ovulate spontaneously. To prevent OHSS, some doctors may trigger egg maturation earlier, use a lower dosage of hCG, or “trigger” using a GnRHa. However, these approaches can compromise egg and embryo quality and reduce the chances of success.
To protect against the risk of OHSS while optimizing egg quality, Physicians can use one of two options. The first is “prolonged coasting,” a procedure I introduced more than three decades ago. It involves stopping gonadotropin therapy while continuing to administer the GnRHa until the risk of OHSS has decreased. The precise timing of “prolonged coasting” is critical. It should be initiated when follicles have reached a specific size accompanied and the blood estradiol has reached a certain peak. The second option is to avoid fresh embryo transfer and freeze all “competent” embryos for later frozen embryo transfers (FETs) at a time when the risk of OHSS has subsided. By implementing these strategies, both egg/embryo quality and maternal well-being can be maximized.
In the journey of fertility, a woman is blessed with a limited number of eggs, like precious treasures awaiting their time. As she blossoms into womanhood, these eggs are gradually used, and the reserves start to fade. Yet, the power of hope and science intertwines, as we strive to support the development of these eggs through personalized treatment. We recognize that each woman is unique, and tailoring the protocol to her individual needs can unlock the path to success. We embrace the delicate timing, understanding that not all embryos are destined for greatness. With age, the odds may shift, but our dedication remains steadfast, along with our ultimate objective, which is to do everything possible to propagate of a normal pregnancy while optimizing the quality of that life after birth and all times, minimizing risk to the prospective parents.