Human Oocyte Cryopreservation:

Recent Studies Reveal the Best Age for Women to Freeze Their Eggs

While there are no guarantees for women hoping to conceive from their own frozen eggs even at the best of times, late last month the Human Fertilisation and Embryology Authority [HFEA] confirmed in a statement that the odds of a future pregnancy for those undergoing oocyte cyopreservation procedures after age 40 are extremely slim -- and may even prove to be risky.While the information comes as little surprise, given it's long been understood that the quality of a woman's eggs diminishes significantly as she ages, it's also relevant because women 40 and older still represent a sizeable share of the market for these services.Regardless of the likelihood of it leading to a successful birth, recent data confirms that the majority of women who freeze their eggs do so in their late 30s, while nearly as many wait until their early 40s before committing to the procedure.Sally Cheshire CBE, Chair of the HFEA, says that women should be cautiously optimistic about egg freezing techniques, but that facilities providing these services have a duty to ensure women are fully informed about what to expect – which apparently may not be the case.“It is so important that women undergoing any type of fertility treatment are fully aware of the risks and cost involved, and the real possibility of it being successful,” informs Cheshire. “Currently women using their own frozen eggs in treatment have a success rate of 18% (30% with frozen donor eggs), which offers no guarantee of achieving a successful pregnancy and birth. Clinics have an ethical responsibility to be clear that egg freezing below the age of 35 offers women their best chance of creating their much longed for family.” 

Difficult choices

Choosing to have a child and when to start trying are obviously pretty big questions in any woman's life. After all, this is a human being you're bringing into the world, and there are few if any responsibilities more important than being a parent.On the other hand, choosing not to have children is an equally challenging life decision. After all, how many childless couples come to regret their choice once they've passed the point of no return, recognizing they'll never have a cute little grandchild to bounce on their knee, or for that matter, loving offspring to look after them when they're too old to look after themselves?Having children might be an easy enough decision for a woman to put off while in her 20s, but by the time she's reached her mid-to-late 30s, with her biological clock ticking seemingly faster with each passing year, the pressure to decide if she wants to conceive or not has traditionally served as a major source of angst.

 Enter egg freezing

For some women, however, the relatively recent advent of human oocyte cryopreservation has significantly reduced this pressure. The widespread availability of egg freezing over the past few years has empowered many women to delay starting their families until such time as they see fit. Being afforded this option can be a true blessing, but it comes with a few caveats.For starters, egg freezing is expensive. Unless you work for a generous tech company like Facebook or Apple, both organizations boasting standing offers to cover the cost of egg freezing for their employees, in the United States you're looking at spending somewhere between $10k and $15k, depending on the number of eggs you freeze and for how long.For most people that's a sizable sum of money, but at the same time, from the perspective of a strict cost-benefit analysis, if you're able to concentrate on climbing the corporate ladder uninterrupted throughout your 20s and most of your 30s, instead of potentially losing an important promotion or job offer while away on maternity leave, $10,000 or so is a comparatively small price to pay.Of course, the question at that point becomes: at which age should you start freezing your eggs? The answer isn't quite as simple as you may think. 

To freeze or not to freeze

A human female is born with a finite number of eggs, approximately between one and two million of them. As she ages, the quality of these eggs diminishes, becoming increasingly difficult to fertilize with every year that goes by. Following this logic it's reasonable to assume that the obvious answer would be to start freezing one's eggs as soon as the decision has been made to do so. But there's a catch.For starters, given the relative newness of human oocyte cryopreservation, no one can yet definitively state that the quality of frozen human eggs will remain stable after a given amount of time. In the UK, for example, regulations are in place stating that frozen eggs cannot be stored for a period longer than 10 years. While most scientists believe that so long as frozen human eggs are properly stored without interruption they should remain consistent indefinitely, at this point in time there is no hard data to confirm it.Another thing to consider is if oocyte cryopreservation is really necessary in the first place. While freezing your eggs in your early 20s will no doubt result in the preservation of a large number of high-quality specimens, for most women it's difficult if not impossible at this age to accurately determine if and when she'll ever actually need them. It's still perfectly feasible, and statistically more likely, that she'll conceive naturally somewhere down the road. Plus, the longer frozen eggs need to be stored, the more expensive cryopreservation becomes.While freezing your eggs as a young adult might bring you the peace of mind of knowing they're likely premium quality, the chances of your finding the right partner and becoming pregnant naturally are statistically still very high. Therein lies the dilemma; if you instead wait until your late 30s or early 40s to undergo the procedure, as most women do, given the reduced quality of your eggs your chances of having a baby via cryopreservation are far less, maybe even impossible. 

The best age to freeze your eggs

 The most recent data dictates that the average age of women choosing to freeze their eggs is 37, which is far more a reflection of their anxiety about becoming too old to conceive than any perceived optimal age to undergo the procedure.The available research shows that the highest incidents of live birth stemming from previously frozen eggs come from women who underwent the procedure prior to turning 30, although most experts agree that the chance of success remains quite favorable up until one's mid-30s, diminishing each year thereafter. According to the HFEA, “if eggs are frozen below the age of 35, the chances of success will be higher than the natural conception rate as the woman gets older.”So looking at this most personal of decisions from the cold perspective of a cost-benefit analysis, most experts agree that it makes the most sense to wait until you're a little older before having your eggs frozen, ideally between 30 and 36. The statistics show that by the time you reach this age you're far more likely to actually use these eggs sometime in the future, sparing you having to undergo a costly procedure unnecessarily, as could well be the situation were you to freeze your eggs in your early 20s.Besides, the available data clearly indicates that the overwhelming majority of twenty-year-old females just aren't especially concerned about someday being too old to conceive naturally. At this age, the best time to start a family simply isn't something too many young women are worried about. There's still plenty of time for everything to fall perfectly into place the good old-fashioned natural way, finding the right partner and becoming pregnant without any need for expensive oocyte cryopreservation.Rather, these are decisions women are taking later on in their lives, and whether they realize it or not, by waiting until their 30s before considering undergoing egg freezing procedures, the data confirms they're pursuing the most pragmatic approach to human oocyte cryopreservation after all, regardless of their original intent.