BCMJ: Social Egg Freezing – A Summary
Summary by: Tavia McLachlan, Director of Special Projects for EVOLVE
Social (or “elective”) egg freezing is not a new concept. What is new is the increase in demand — the number of patients in their 20s & 30s requesting referrals from their GP is on the rise. Whether it be the involuntary “life pause” imposed by the Pandemic, or social influencers chronicling their experience, the conversation has become increasingly mainstream over the past few years.
Since 2012, when the term “experimental” was removed from the procedure, elective egg freezing has been a viable option for fertility preservation. Below, we summarize an informative article published in the BC Medical Journal on why egg freezing is needed, how it works, success rates, and concerns to advise your patients about.
The first human oocyte preservation (egg freezing) was done in 1986. Initial attempts utilized a slow-freezing method that had poor success rates. This method was only used as a last resort for patients who were most likely going to become sterile due to chemotherapy. With the introduction of vitrification (fast-freezing), success rates have dramatically increased, now matching those achieved with fresh eggs (of the same age).
The article states that egg freezing is currently the only way for females/assigned females at birth (AFAB) to match the fertility potential of males/assigned males at birth. Why is this? Well, spermatogenesis takes a little over 2 months and continues throughout a male’s life. In contrast, a female is born with all the eggs they will ever have. Throughout life, ovarian reserve depletes. Most notably, between ages 35-39 they will go from 200, 000 eggs to less than 40,000. Additionally, aneuploidy, or chromosomal abnormalities, become more common; age-related deterioration and the effects of the environment take a toll on egg quality over time. Both decreasing numbers and decreasing quality (leading to chromosome abnormalities) contribute to reduced fertility with age As stated in the article, “by 43, only 16.6% of embryos were chromosomally normal”.
These are the facts, but what is the issue? The average age of trying to conceive has increased. So individuals are no longer trying to conceive at 25. Egg freezing provides the solution.
Egg freezing involves the following steps:
- Ovarian reserve assessment on the patient
- Personalized treatment plan/protocol for patient
- A patient will take ~ 10 days of FSH and LH before the eggs are prompted to mature by triggering their release
- Outpatient procedure is performed on the patient by REI to aspirate the fluid from each ovarian follicle (removal of eggs)
- An embryologist will isolate mature eggs and prepare them to freeze
- Vitrification of mature eggs is performed
The stats …
Most evidence comes from countries where egg donation is legal. Most donors are in their 20s and, as we know, age heavily influences egg quality. The egg survival rate in this study was 90.4%. The authors noted it may be unrealistic to expect the same of all social egg freezing results as patients often are in their 30s before undergoing this process.
In 2016, a study was done specifically on social egg freezing. The results of the study were broken out into two age groups:
For women who were 35 or younger at the time of freezing, the average live birth rate per 10 eggs was 60.5%.
However, for women over 35, the rate dropped significantly to 29.7% per 10 eggs.
Both sets of numbers were in line with IVF success rates of women in matching age groups. All the data supports that freezing earlier, much like going through IVF at a younger age, always has better success rates than later.
In addition to looking at pregnancy rates the authors also looked at the number of eggs needed for one healthy baby. On average 8-10 eggs, before the age of 36 are considered the best chance for success. Of note, is that younger patients respond better to treatment and have more eggs to retrieve at the time of aspiration, so this is in favour of a younger start as well. The main concerns outlined in the article were ethical in nature.“Ethicists have stated that the health care providers should ‘frame discussions’ about egg freezing… To assist people in making informed choices”. The research also cites health concerns with advanced age gestation; specifically cardiovascular and other physical demands of pregnancy and delivery.
Overall, the article concluded egg freezing is a safe and viable option to preserve and extend fertility potential by 2-10 years. The financial barriers to egg freezing do not make it available to everyone. However, with the increase in health spending accounts, flexible medical plans and the coverage of fertility treatments and drugs, more people may take advantage of social egg freezing.
You can read the full article at BCMJ.org here.