Social Egg Freezing
Social egg freezing refers to the freezing of eggs to guard against the natural age-related decline in female fertility.
In Canada, the average age at which women have their first child is increasing and more than half of all births now occur in women over the age of 30. The postponement of parenthood has increased the probability that women will reach an age at which the quantity and quality of their remaining eggs prevents spontaneous conception if/when such conception is desired.
As a result many women are consulting fertility centers to better understand if egg freezing could be a good option to improve their future fertility.
How Is Social Egg Freezing Done?
After an initial consultation, appropriate blood testing plus diagnostic ultrasound and the decision to proceed ahead, egg freezing involves ovarian stimulation, egg retrieval and vitrification of the mature eggs
Ovarian stimulation is done with daily injections of follicle stimulating hormone (FSH). Typically, you will be on FSH injections for about 10 days before you are ready for your egg retrieval. The first several days of gonadotropin administration are usually free of symptoms. However, after about a week you may experience abdominal tenderness or bloating.
During the time your ovaries are being stimulated you will be closely monitored with ultrasound scans. At each ultrasound we document the size and number of follicles, and we may make adjustments to your medications to optimize your stimulation.
Once enough follicles reach a certain size we will schedule your egg retrieval. Approximately 36 hours before your egg retrieval you will take a different injection to promote the maturation of your eggs. This final injection is critical to the success of your egg retrieval.
Egg retrieval involves a transvaginal ultrasound probe with a needle guide. Using sterile technique the needle will pass through the vaginal wall directly into the ovary on each side. As each follicle is punctured, the fluid is drained and sent to the lab where it is examined under a microscope by an embryologist to identify each egg.
The night before the procedure you will be prescribed Ativan to help you rest and feel relaxed the morning of the procedure. You will be instructed not to eat or drink anything the day of the procedure, and to arrive at the Montreal Fertility Centre one hour prior to the egg retrieval. On your arrival a nurse will take your vital signs and start an intravenous (IV). Egg retrieval may cause some discomfort but takes only 10-15 minutes. In the procedure room you will receive medications to minimize discomfort.
On a large screen TV you will see how the physician is collecting your eggs.
Following the egg retrieval you will be monitored in the recovery room before returning home. By the next day you will know the total number of mature eggs that we were able to freeze for you.
Do not plan any other activities for the day of your egg retrieval and plan to have someone available who can drive you home after the procedure. When you arrive home, relax and have an early night. It is not uncommon to have some abdominal discomfort and light vaginal bleeding post retrieval.
What Are The Costs?
Most, but not all, medication costs related to ovarian stimulation are covered by private insurance companies or the RAMQ provided you have a valid RAMQ card and a signed Medicament d’Exception form.
For up to date information on what we charge for an egg freezing cycle please consult the "Fees" section of our website. Please note that our fee for egg freezing includes the costs of storage of the eggs for the first year. After that an annual storage fee will apply until you either return to use them or advise us that they are no longer wanted.
Please also note that if/when you return to use your frozen eggs you will be charged for thawing the eggs, fertilizing them with the ICSI, growing the embryos in the incubator and then performing an embryo transfer and/or embryo freezing. Again for up to date information for the costs of thaw/ICSI frozen eggs, embryo cryopreservation or a frozen embryo transfer cycle please consult the "Fees" section of our website.
What Are The Success Rates?
Clearly, the goal of freezing eggs is to “lock-in” the success rate that would be expected if a fresh IVF-ICSI cycle were being performed at that age.
Although the first live births after egg freezing occurred over 30 years ago, egg freezing for social reasons is relatively new and the data is preliminary.
The best available information suggests that:
- Freeze-thaw egg survival rates are between 80-90%
- Fertilization rates of frozen-thawed eggs are between 70-80%
- Embryos derived from frozen-thawed eggs may be slightly less likely than fresh eggs to develop into high quality blastocysts
- Clinical pregnancy rates and live birth rates appear to be similar to the rates obtained from fresh eggs
There is no doubt that the age at which a woman freezes her eggs and the number of eggs that she is able to freeze impact the probability that these eggs will enhance her future fertility.
Although we do not yet have robust national statistics for social egg freezing, the cumulative live birth rate in Canada per batch of fresh eggs retrieved, fertilized and then used including all embryos (fresh + frozen) from 2013-2014 was as follows:
|
Number of mature eggs retrieved |
Age of Oocyte Provider |
||||
|
Less than 30 |
30 – 34 |
35 – 37 |
38 – 40 |
41 – 42 |
|
|
<5 eggs |
20.3% |
21.3% |
17.0% |
11.7% |
5.9% |
|
5 – 9 eggs |
35.6% |
38.3% |
31.4% |
23.8% |
13.4% |
|
10 – 14 eggs |
46.8% |
45.3% |
41.9% |
31.8% |
21.8% |
|
15 – 19 eggs |
46.8% |
51.1% |
45.5% |
33.2% |
30.3% |
|
Total |
38.5% |
38.3% |
30.9% |
21.8% |
12.5% |
Success rates with social egg freezing in Canada will probably approximate these percentages.
A recent review (Fertility & Sterility, Kawwass et al. 2021) of the results from oocyte thawing for all cycles done in the USA from 2014-2018 reported the following outcomes:
|
Age at Freezing |
<35 |
35-37 |
38-40 |
41-42 |
>42 |
|
Avg # of Thawed Eggs |
10.6 |
10.8 |
10.1 |
9.1 |
6.1 |
|
Avg # of Embryos Available for Transfer or Freezing |
2.7 |
2.7 |
2.5 |
2.5 |
1.8 |
|
Cumulative Live Birth Rate (Fresh + Frozen embryos) |
35% |
30% |
17% |
10% |
< 5% |
What Are The Risks?
The risks of ovarian stimulation and egg retrieval are minimal. Ovarian stimulation may result in bloating and abdominal discomfort, particularly in the days immediately surrounding the egg collection. There is a risk of ovarian hyperstimulation syndrome (OHSS) but this risk is <1% with the trigger medication that we use, and even if it occurs is likely to be quite mild.
The egg collection itself could cause bleeding or infection. However, again, in our experience these risks are extremely low (<1%) and can be promptly corrected.
It is important to recognize that not all follicles will yield an egg and that not every egg is likely to be mature/freezable. There is a chance (<5%) that no mature eggs will be obtained at the egg retrieval.
Other risks include:
- The chance that frozen eggs may not survive the thaw
- The chance that thawed eggs may not fertilize
- The chance that the fertilized eggs may not develop into viable embryos
- The chance that pregnancy may not occur
- The chance that pregnancy may end in miscarriage
- The maternal risks of pregnancy at a later age, such as gestational diabetes, hypertension, cardiovascular complications, caesarean section, etc.
- The fetal risks of pregnancy including malformations, chromosomal abnormalities, impaired growth, etc.
Finally, it is important to recognize that after the egg collection/freezing there is a distinct possibility that none of the frozen eggs will ever be needed.
What Is The Ideal Age To Freeze Eggs?
The highest probability of live birth in egg freezing programs has been obtained when eggs are frozen before age 36. Natural fertility begins to decline in the 30s and this decline accelerates after age 35.
Nevertheless, the greatest cost-benefit appears to occur when women freeze their eggs between age 35-37. This is not unexpected since women in their early 30s have relatively stable fertility rates, and the marginal benefit of freezing eggs becomes magnified only when the success rates at the age of freezing are very different from the success rates that a future fresh IVF cycle could provide.
For example, the success rates with frozen eggs at age 25 vs. fresh eggs at age 33 (8 years later) are quite similar. In contrast, the success rates with frozen eggs at age 36 would be significantly better than the success rates with fresh eggs 8 years later at age 44 when the only viable option might be an egg donor.