Egg freezing is going mainstream in the US. There are even mobile vans, painted in bright yellow, which advertise egg-freezing services direct to potential clients. They visit female gym classes, hair-stylists and nail bars aiming to pick up women in the right demographic i.e. in their early thirties with disposable income.
These services, which are usually not available within standard health insurance packages, are undoubtedly expensive, at an average of $10,000 USD. Plus there is an annual storage fee.
Clearly then, one feature driving the boom in egg freezing is female financial empowerment. But that can’t be all, because female financial empowerment has been a more-or-less gradual phenomenon over the last few decades. The other feature is improvements in medical technology, and this is what makes it more attractive these days.
There have been significant breakthroughs in the science of fertility made over the past 10 years, and there are two factors playing a part. Firstly, a process that allows doctors to flash-freeze eggs and secondly improvements in the IVF process that unites a thawed egg with sperm in a petri dish in order to make the embryo.
Yet, at this moment in time, the vast majority of frozen eggs at clinics are yet to be thawed. So questions remain unanswered.
Will the eggs all be viable after long-term freezing?
And can we really safeguard our fertility by freezing our eggs?
Let’s take a look at the process of egg freezing
The human egg is among the largest cells in the body and does not freeze well. This is because it is made mostly of water, which forms ice crystals when it freezes. These crystals, like microscopic shards of glass can damage the extremely delicate structures inside the cell. Because of this, for years, freezing an egg meant dehydrating it and then introducing a kind of antifreeze to prevent ice crystals. It was then cooled very slowly, degree by degree over a period of hours.
For years freezing an egg entailed dehydrating it to the fullest extent possible, then introducing tiny amounts of cryoprotectant, a kind of antifreeze that aims to prevent crystals from forming. Everything was done very slowly. Thawing, likewise, was a long, painstaking process as liquid water in the cell could, at any moment, revert back to ice causing irreversible damage to the cell.
This all changed back in 2007 with the process of ‘vitrification’. In this process the eggs are frozen breathtakingly fast. So very fast, in fact, that larger ice crystals do have time to form. Essentially the eggs are plunged into a liquid nitrogen bath of between -195C or -320F and instantly transform into a kind of glassy state. Hence the word vitrification, which is related to the Ancient Latin word for glass.
Recognised success
When the time comes to use the eggs, a process of rapid thawing comes into play. The results are, without doubt, excellent! So much so that the ethics committee of the American Society for Reproductive Medicine (ASRM) issued a paper in 2018 saying, “Egg freezing for women attempting to safeguard their reproductive potential for the future should now be considered ethically permissible.”
There is some debate over whether frozen eggs are as viable as fresh, but most experts say they are very close. And there is no question that eggs frozen when a woman is 32 are better than fresh eggs retrieved from the same woman at 42.
Of course, great eggs do not necessarily mean pregnancy success. It also is the continuing improvements in IVF techniques that work in hand-in-hand with the promise of egg freezing to make the whole proposition viable.
For instance, one of the biggest steps here has been implantation of embryos at the blastocyst stage (5 day incubation in the lab as opposed to the traditional 3 day incubation period before implantation), which has improved outcomes for women of all ages undergoing IVF.
Who knows? In a few years when all those frozen eggs start being thawed, we’ll have even better technology and the answers will be clearer. In the meantime it is probably best to bear in mind the advice of one of the experts in the area, “We have to repeatedly say to patients that there’s not an actual baby in the freezer, there is the potential for a baby.’”
