A primer for Canadian women on freezing your eggs

Back in 2014, Facebook and Google made headlines when they started covering the cost of freezing eggs for women who want to freeze their own eggs for possible use later in life. Other companies in the tech sector like Spotify, Amazon, Citibank and Microsoft quickly followed suite.

Egg freezing is catching on north of the border. Though the actual numbers are still relatively low, the number of Canadian women opting to freeze their eggs has increased in recent years. According to a report by BORN Ontario (Ontario's pregnancy, birth and childhood registry) the number of women who underwent the procedure more than doubled from 132 in 2013 to 325 in 2016.

Canadian women have been freezing eggs for medical reasons before undergoing chemotherapy, for example for about a decade, but egg freezing for non-medical reasons (aka 'social' egg freezing) has been available for about half that time.

Dr. Niamh Tallon is a fertility specialist at the Olive Fertility Centre in Vancouver. I asked her whether she's seen an uptick in the number of women interested in social egg freezing; "absolutely," she replies, "I probably see one patient a day [who asks about it], though they don't all freeze their eggs."

The procedure works on the principle that a woman's fertility decreases over time, not only because of a decrease in the actual number of eggs she has, but also because of an increase in the proportion of non-viable eggs in her supply. This proportion increases dramatically in a woman's late thirties and early forties, and so freezing eggs in a woman's twenties and early thirties for her to use later on when she's ready to conceive - should she not be able to conceive naturally - provides a backup stock of healthy eggs to use, and thereby potentially extends a woman's number of reproductive years.

For this reason, Dr. Tallon, says "we recommend freezing for women under the age of 38. Over 38 is where you see a dramatic decline in overall egg number and an increase in the genetic abnormality of eggs."

Every woman is different in terms of their egg count and quality, so rules of thumb may not apply to everyone. And, says Dr. Tallon, for "women who are over 38 and there's no alternative, if they understand the likelihood of success, freezing eggs may still be worthwhile, even if it gives them a lower chance of success."

Needless to say, freezing eggs is a much more invasive procedure than donating sperm, involving daily hormone injections, transvaginal ultrasounds, and a surgical procedure under local anesthetic to remove the eggs. Finally a round of in vitro fertilization (IVF) is required when it's time to implant the eggs.

And without an employer picking up the tab, it's a pricey endeavor. Costs vary depending on the clinic, but are usually in the region of $10,000 to extract and freeze the eggs, $300 per year to store them, and $6,000 to cover the cost of one IVF cycle. So far no provincial health plans cover the cost to freeze eggs, though Ontario does offer coverage for one round of IVF and tax credits for IVF drugs. Other provinces like Manitoba offer residents tax credits, and companies like Starbucks Canada have also started covering IVF for their Canadian employees.

Recent technological advances mean that the rates of success have improved enormously in the last few years. Egg vitrification, a technique in which an egg is dehydrated before being flash frozen, has taken off since 2013 when the American Society of Reproductive Medicine okayed it for use in the US. Egg vitrification is so effective, says Dr. Tallon, that 90% of eggs frozen using this method survive.

Ultimately, deciding whether or not to freeze your eggs is a highly personal decision. But no matter what, Dr. Tallon says it's important to keep in mind that "egg freezing is certainly not a guarantee."

If you do want to know more, look up one of the many clinics across Canada now offering the procedure, or speak with your GP.

Miranda Elliott has a Masters in epidemiology and works in public health.