The ability to freeze and thaw embryos successfully is one of the greatest advancements in assisted reproductive technology (ART). Many fertility patients who undergo in vitro fertilization (IVF) reap the added benefits of frozen embryos. Embryo freezing—cryopreservation—has existed for many years, but earlier techniques were associated with undesirable ice crystal formation. Vitrification, a flash or fast-freeze technology, has greatly improved outcomes from cryopreserved embryos. Patients who use frozen embryos now experience success rates equal to, or better than, those from fresh embryo transfer cycles.
Who will have access to frozen embryos after an IVF treatment cycle?
At Shady Grove Fertility, our physicians can determine the probability that any given patient will have embryos available to freeze following an IVF cycle. Our unique outcome prediction algorithm takes into account approximately 15,000 treatment cycles from nearly 10,000 Shady Grove Fertility patients since 2009. Known as the Richter Predictor (named for SGF’s Chief Statistician and Co-Director of Research, Kevin Richter, Ph.D.), this model uses your personal test results—antral follicle count, anti-Müllerian (AMH) and follicle-stimulating hormone levels (FSH), and the presence or absence of uterine and sperm abnormalities to predict IVF cycle outcomes. This real-data-driven model provides personalized predictions regarding not only the likelihood and average number of cryopreserved embryos, but also the potential increase in chances of live birth from your egg retrieval, if you should have frozen embryos available after your IVF cycle.
While not all patients will have embryos available for freezing after a fresh IVF cycle (you must go through a fresh cycle using medication to stimulate the ovaries, then have your eggs retrieved and fertilized in the lab before freezing can ever occur), patients with good ovarian reserve have an excellent chance of freezing surplus embryos for the future.
The Advantages of Frozen Embryos
- Frozen embryos provide patients with additional cycle opportunities.
Having frozen embryos allows you additional opportunities for success from a given egg retrieval. If your fresh transfer is unsuccessful, frozen embryos may provide the possibility of trying again without having to take ovarian stimulation medication or to have another egg retrieval. The development of vitrification technology has led to outstanding outcomes, with more and more patients achieving live birth from a single stimulated cycle.
- Frozen embryo transfer (FET) cycles are less costly than fresh cycles.
Following a fresh IVF treatment cycle, subsequent FET cycles are less costly for patients. Expenses of both medication and treatment are less than in a fresh cycle. Costs of treatment are reduced since there are fewer monitoring visits, and there is no need for egg retrieval, insemination, or embryo culture. In addition, Shady Grove Fertility is currently conducting a clinical research study on FET. If you choose to participate, your medications will be provided to you free of charge.
- An FET cycle is easier.
For many of our patients, FET cycles are easier because you do not need surgery (the egg retrieval) or anesthesia. At the start of your FET cycle, estrogen injections are used to prepare the uterine lining and are administered only once every three days. Daily intramuscular progesterone is added later in the cycle.
- Clinical Trial Opportunity: Shady Grove Fertility is currently recruiting FET patients for a study comparing vaginal progesterone replacement to injections. Medication costs for participants are 100 percent covered, and participants have a 2 in 3 chance of receiving fewer or no progesterone injections. Please speak with your nurse or physician for more information.
4. Freezing all embryos for future FET(s) overcomes the negative effect that elevated progesterone levels have on pregnancy outcomes.
Recent research has shown that if a woman’s progesterone levels rise during the ovarian stimulation portion of her treatment cycle, the endometrium (or uterine lining) is less receptive to embryo implantation, and pregnancy rates are reduced. If progesterone rises above a critical threshold, your physician may recommend that you freeze all available embryos rather than proceeding with fresh transfer. An FET can then be performed in a cycle without stimulation medications. Data from Shady Grove Fertility research studies has demonstrated that transferring the embryo(s) via FET is associated with a greater chance of success than fresh transfer in the setting of an elevated progesterone level. Women who have a ‘freeze-all’ cycle experience the same excellent live birth rates as do women who have a fresh transfer (and normal progesterone levels) prior to their FET.
- FET allows patients to reduce their risk of ovarian hyperstimulation syndrome while maintaining excellent success rates.
We closely monitor patients for ovarian hyperstimulation syndrome (OHSS) and utilize stimulation protocols designed to prevent this from occurring. Thus, OHSS is rarely seen in our practice, occurring in less than 1 percent of patients. However, in situations where a physician sees potential warning signs that a woman is at high risk for OHSS (high estrogen levels and follicle numbers, rapid weight gain, fluid in the pelvis, etc.), he or she may recommend freezing all available embryos rather than proceeding with a fresh transfer, as pregnancy may increase OHSS risk. Embryo(s) can then safely be transferred via FET. As with freeze-all cycles for elevated progesterone levels, pregnancy rates remain favorable.
- Frozen embryos allow for genetic testing.
For couples with a risk of passing certain genetic conditions onto their children, we can test the embryos for certain genetic mutations. This is called preimplantation genetic diagnosis (PGD). After the physician retrieves the eggs and they are fertilized, the embryologist will biopsy each suitable embryo on day 5 or 6 of development. The embryologist will then freeze the embryos while awaiting results from the biopsied cells. The physician can then transfer only embryo(s) for which testing indicates the genetic mutation (and corresponding medical condition) in question is absent.
In addition to testing for genetic mutations (PGD), embryo freezing has allowed for preimplantation genetic screening (PGS). PGS looks for abnormalities in chromosome number, such as trisomy 21, which causes Down’s Syndrome, and many others that are likely to result in implantation failure or miscarriage. Likely candidates for this testing include patients with recurrent pregnancy loss and older women, who are at higher risk for chromosomal abnormalities. In appropriately selected candidates, this testing may result in improved live birth rates.
- Frozen embryos offer the potential to grow your family at a later date.
Vitrified embryos maintain reproductive potential far into the future, giving our patients time to make the decision to expand their families. While women can only go through FET at SGF until the age of 51, FET can suspend the proverbial biological clock, since embryos thawed for FET maintain the reproductive potential associated with the age of the egg at the time it was fertilized. For example, if a woman has her first child at 38 through IVF and has remaining embryos cryopreserved, she can come back to have embryo(s) transferred via FET, at a time when conceiving with her own eggs would otherwise be unlikely.
Evidence-based medicine and years of research performed at SGF has allowed for our patients to have better treatment options than ever before, with frozen embryos at the forefront of this care revolution.
If you would like to learn more about frozen embryos at Shady Grove Fertility or to schedule an appointment, please speak with one of our New Patient Liaisons at 877-971-7755.