By Pauline Cottee
As an embryologist, we are often asked questions by our patients that leave us feeling like a deer in the headlights. While we are equipped with first hand experiences and solid research, for me, egg freezing is one of those areas. The technique of oocyte freezing was originally designed for women to preserve their fertility before embarking on chemotherapeutic and/or radiation treatments which would otherwise destroy the genetic material of their eggs and any chances of using their own biology for their offspring.
Nowadays, companies such as Apple, Facebook and Google are offering women within their companies the opportunity to freeze their eggs so they can focus on career progression knowing that they have preserved some of their “younger” eggs. Similarly, many single ladies also opt to freeze eggs as a fertility investment for when they do eventually meet their partner and wish to start a family. This concept has also led to a rise in “egg-freezing” parties arranged by fertility companies to specifically market this technology to single, career minded women.
The deer in the headlight question for me is “how many eggs are enough to make a baby, or two”. It’s a question that is, whilst very important, often very casually mentioned to a scientist either just before or immediately after the oocyte collection. And it is a very hard question to answer.
While this question can be answered by statistics we’ve collected in the lab, or to rely from statistics generated from other labs, at the individual level, it’s very difficult to know where one fits in the grand statistical scale and how to precisely answer how many eggs in storage are enough. One of the leading specialists in this area, Dr Nicole Noyes has shown through her work that for women aged less than 37 years old, 8-10 eggs should be banked, from 37 years to 40 years of age, 15 oocytes should be preserved and women greater than 40 years of age should consider storing 20 oocytes to achieve one live birth. And of course, these numbers aren’t a magic formula; it too, is also an average of what women in these age groups need to achieve a pregnancy and live birth.
With this in mind, these figures can be quite daunting to women who are challenged with life threatening illnesses that may not be able to afford the luxury of time to accrue such numbers. Similarly, those storing oocytes for future fertility investment may not be able to financially afford to repeat back to back cycles to preserve so many eggs. It also begs the question for women who have the opportunity to egg freeze through their work, are their companies allowing multiple cycles to be covered in their insurance plans? And do they also help cover the costs of thawing oocytes and using them in an IVF cycle?
If this wasn’t enough, one then has to consider that once oocytes are thawed and committed to an IVF cycle, they then endure the same level of declining success as any other IVF cycle would. There is a risk it could fail. There is a risk that an embryo could be genetically abnormal (because this can happen to younger women too). There is a risk of implantation failing, or no heartbeat in the foetus at the 6-week scan. This is a lot of pressure on a cohort of eggs (fresh or frozen). At this point you may be reading and wondering why on earth anyone would do this? I guess it’s like taking out a life insurance policy. You hope to god that you will never actually need it, but there is comfort knowing there is something to fall back on if needed. The technology does work. There are live births. For women fighting life threatening diseases or those working hard to get their careers going, this is not a bad thing to do. But one does have to be somewhat realistic of the oocyte numbers needed and the costs involved to achieve that “baby or two”.
If you have any questions, or would like links to the articles used for this blog, please do not hesitate to get in contact with us. As always, please discuss your medical plan with your fertility specialist.
Best of luck!
Pauline
