Today I was giving a lecture to UBC medical students on IVF. I reviewed how we stimulate the ovaries to produce multiple eggs, how the eggs are fertilized to make embryos, and how embryos are grown in the lab. I then detoured into other aspects of IVF, including its use in fertility preservation, specifically egg freezing.
In standard IVF, multiple eggs are retrieved from a woman's ovaries and we fertilize them and make embryos. More and more though, we are not fertilizing them and, instead, are freezing them as (unfertilized) eggs. Originally we were freezing eggs only for single women who had cancer or were at risk of running out of eggs early for other reasons (i.e. premature ovarian failure). Back then, the pregnancy rates from frozen eggs were very low (5%). Today, pregnancy rates from frozen eggs are very good (50%) as we now vitrify eggs. As a result, we are currently freezing eggs for non-medical reasons, and this practice is supported by the American Society of Reproductive Medicine. We freeze eggs to preserve a woman's fertility while she is young so that the eggs will be available for use when she is older - at a time when she would have few or no eggs or her eggs would be of such poor quality that she can't get pregnant with them. This type of egg freezing, called "social egg freezing," is becoming more and more popular. It gives women who know they want children one day the ability to save their eggs today.
The pregnancy rate from frozen eggs is not 100%, though, so there remains a chance that a woman who freezes her eggs won't have a baby from those eggs in the future. As a result, I am still advising women to consider conceiving now rather than waiting for later and relying on frozen eggs cto have children. Furthermore, the success rate of egg freezing decreases with age. Egg freezing after the age of 40 is not recommended as the pregnancy rates are very low (< 20%). Egg freezing costs about $9000 total (including medications) and then a $200 per year storage fee.
Sophia Vergara, from the sitcom Modern Family, recently announced that she is freezing her eggs at the age of 40. I commend her openness on the topic of fertility preservation. I do wish she would conceive now as I worry that her 40-year-old frozen eggs will give her a fairly low chance of pregnancy. Further waiting to conceive until the later 40s is associated with an increased risk of pregnancy complications. In my opinion, freezing her eggs to delay pregnancy might jeoparadize the chance she bring another funny person into the world. I am not sure if she reads my blog, though.