One of the most difficult parts of our practice is to counsel patients after a failed IVF cycle.
After investing an enormous amount of time, emotion, and financial resources, a negative result can be devastating. The post-IVF meeting allows the physician and patient to review the cycle, answer questions, and hopefully, come up with a better treatment plan for the future. At IVFMD, we analyze the following factors to find the causes of IVF failure:
1. Egg Quality
The egg is the first and most important factor to be considered during the analysis for the causes of IVF failure. The egg provides the majority of the ingredients required for successful fertilization and embryo development. Once the sperm enters the egg, it triggers a series of biochemical reactions that lead to the formation of the male and female pronuclei, which then fuse to combine the the parents’ genetic material to create the embryo. The single cell embryo subsequently divides into daughter cells through a process regulated by the organelles that reside within the cytoplasm of the egg. As the cells divide, the chromosomes from the original cells migrate along special pathways (the mitotic spindles) into the daughter cells. With time, these migrating tracts can become defective resulting in abnormal separation of the chromosomes. The result is an embryo with an abnormal number of chromosomes that, depending on the severity of the error, may stop growing at an early stage in the lab or eventually ends as a biochemical pregnancy or first trimester miscarriage.
Age has a great impact on the egg. After age 30 egg quantity and quality begin to decline and the rate accelerates after age 35, so that by age 40 only about 10% of a woman’s eggs are normal. The decrease in egg number, when combined with poor egg quality, often translates into a lower chance of creating a normal embryo with IVF.
A poor grading score of the transferred embryo can provide the first clue to why the cycle fails. Most IVF labs currently use a grading system based on the appearance of the embryos to choose the best embryo for transfer. In general, the “prettier” the embryo looks (symmetrical cells, fewest fragmentations, large inner cell mass, advanced stage), the more likely that it will implant and result in a live birth.
However, there is no guarantee that a nice looking embryo will be a normal embryo. Only by biopsying the embryo for chromosomal analysis can the makeup of the embryo be known.
2. Sperm Quality
The genetic material packed within the sperm head may be abnormal even when a routine semen analysis shows normal sperm concentration, motility, and morphology. Damage to sperm DNA can be caused by exposure to chemicals, free radicals and oxidants (byproducts of metabolism), and tobacco use.
Injecting a single sperm into the egg (ICSI) can raise the chance of fertilization but does not ensure that a normal sperm has been chosen. Fertilizing an egg with an abnormal sperm can result in an abnormal embryo.
At IVFMD, we use the Halosperm test to assess the integrity of sperm DNA. Research has shown that broken DNA in sperm does not disperse after acid denaturation. In contrast, normal sperm DNA disperses after special acid treatment to produce a halo of DNA chromatin around the sperm head. Sperm that do not show the halo with the Halosperm test are thought to contain damaged DNA. When 30% or more sperm have fragmented DNA, the sperm sample is considered to be abnormal.
How can we select sperm with intact DNA for ICSI ?
Mature sperm with normal DNA bind readily to hyaluronan, a special protein on the shell of the egg. To increase the probability of choosing a sperm with normal DNA, we use the PICSI kit, which contains wells covered with hyaluronan. Sperm are added to the well and within minutes, mature sperm with normal DNA bind to the hyaluronan layer in the well. By selecting the bound sperm for ICSI, we can increase the likelihood of choosing an optimal sperm for fertilization. In addition, we recommend antioxidants to men with abnormal Halotest results for at least 3 months prior to future IVF cycles.
3. The Stimulation Protocol
In the event of a failed cycle, the stimulation protocol is reviewed for possible improvement. Important decisions to be made during stimulation cycles are: type of protocol, starting dose of stimulation medications, and timing of the HCG trigger shot.ect sperm with intact DNA for ICSI? Mature sperm with normal DNA bind readily to hyaluronan, a special protein on the shell of the egg. To increase the probability of choosing a sperm with normal DNA, we use the PICSIR kit, which contains wells covered with hyaluronan. Sperm are added to the well and within minutes, mature sperm with normal DNA bind to the hyaluronan layer in the well. By selecting the bound sperm for ICSI, we can increase the likelihood of choosing an optimal sperm for fertilization. In addition, we recommend antioxidants to men with abnormal Halotest results for at least 3 months prior to future IVF cycles.
Understimulation with a low starting dose of stimulation medications or prolonged pituitary suppression with Lupron and/or the birth control pill can result in slow ovarian response. The result is a protracted stimulation cycle that ultimately costs more and yields a low number of mature eggs.
Cycles that require more than 12 days of stimulation have been associated with lower rates of pregnancy.
Hyperstimulation, on the other hand, can also contribute to treatment failure. Very high estrogen levels (over 4,400 pg/mL) can accelerate endometrial maturation and lead to a mismatch between the ages of the embryo and uterine lining. The implantation rate is reduced when the endometrium is “older” than the embryo. A day 5 blastocyst, for instance, will be less likely to implant on an endometrium that has been exposed to 6 days of progesterone.
The endometrium can age prematurely due to early rise of progesterone during the stimulation phase. Progesterone levels of over 3.5 ng/mL on the day of HCG trigger have been associated with a lower rate of pregnancy. Premature rise of progesterone can be caused by delaying the HCG trigger a bit too long, or by inadequate pituitary suppression (with either Lupron or Ganirelix, or Cetrotide).
At IVFMD, we do our best to assess each patient and design a stimulation protocol that fits her unique requirements. Unfortunately, despite the best planning, the outcome can be unpredictable. In the event of a failure, however, data gathered from the previous cycle can help choose a new stimulation protocol that can yield a completely different ovarian response and outcome.
4. The HCG Injection
HCG (Human Chorionic Gonadotropin) activates the final transformation of the egg to make it fertilizable by the sperm. HCG also frees the egg from the follicular wall so that it can be easily aspirated during retrieval. Correct timing of the HCG trigger is critical for a successful cycle.
- Giving HCG too early can result in a collection of few mature eggs. The typical ovarian stimulation lasts between 10 and 12 days. Administration of HCG after only 8 or fewer days of ovarian stimulation can result in collection of few mature eggs.
- Giving HCG too late can allow the progesterone level to rise and make the endometrium less receptive to the embryo. The eggs can also become too old (post-mature), with a dark and shrunken cytoplasm. These eggs usually do not fertilize well, or if they do fertilize become poor-quality embryos.
- Suboptimal HCG action on the follicles can also result in the collection of few mature eggs. Inadequate HCG action can be caused by incorrect injection technique, faulty medication (i.e. a drug that has expired or has been exposed to extreme temperatures), or poor absorption into the bloodstream after local subcutaneous injection. An HCG level of below 80 mIU/mL 1-2 days after the injection suggests inadequate vascular absorption and thus necessitates a second dose. Deep intramuscular (IM) injection of HCG (vs. subcutaneous) can help deliver HCG directly into the bloodstream.
5. The Endometrium
Suboptimal endometrial growth is one of the major causes of IVF failure and is one of the most difficult problems to overcome. At IVFMD, we like to see an endometrium of at least 7mm on the day of HCG. An obvious cause of thin lining is intrauterine adhesions from previous surgery (D&C, myomectomy, septum resection). However, a patient without surgery can still have a thin endometrium. For some patients, suboptimal endometrium can be attributed to poor uterine blood flow; unfortunately, for most cases the etiology remains unknown.
To improve a suboptimal endometrium in a future cycle, we recommend an endometrial biopsy before the stimulation cycle. Research had shown that endometrial biopsy stimulates tissue remodeling that causes local release of factors that promote implantation. Estrogen and Viagra can also be used vaginally at the start of the stimulation cycle to improve uterine blood flow. In addition, acupuncture is believed by some to enhance endometrial receptivity but the scientific evidence is lacking.
6. The Embryo Transfer
The embryo transfer procedure is one of the most important factors that influence the outcome of an IVF cycle and is very physician dependent. A smooth and gentle transfer avoids injury to the endometrium that can cause bleeding and cramping. At IVFMD, prior to the stimulation cycle, a trial transfer is routinely performed to map the uterus and determine the optimal placement site for the embryo. If a difficult transfer is anticipated, measures can be taken to ensure a successful transfer. Placement of a cervical traction stitch after egg retrieval can help counteract a sharply tilted uterus. Ultrasound guidance can also be helpful in guiding the transfer catheter to the appropriate site.
7. The IVF Laboratory
Finally, we review the progress of the embryos during the culturing period. If the embryos do well during the first 3 days of culture but develop slowly afterward, earlier transfer on day 3 in future cycles may be considered, especially if the patient is 38 years or older. Since the uterus is the best incubator, embryos that do not grow well in the lab can be transferred earlier in order to have a better chance to survive.
We also review the laboratory process for anything unusual. The temperature and gas profiles in the Embryology Laboratory and within the incubators are closely reviewed. Laboratory reagents (such as culturing media and layering oil) that are in close contact with the embryos must pass strict quality control tests by the manufacturer, and once arrived, have to pass our own quality control tests before they can be used.
Often, even after an exhaustive review of the above factors, no clear cause can be found to explain for the treatment failure. Even when the embryos are tested for chromosomal abnormalities using the most advanced technology currently available, transfer of supposedly the normal embryos results in clinical pregnancy in only 70% of cases. We are thus reminded that although IVF can facilitate the union of sperm and egg, it cannot guarantee the miracle that is life.