Fertility preservation is a topic that is (thankfully) being discussed more often, however the next decision—whether to freezing eggs or embryos—often is not.
The fundamental difference between an egg and an embryo is that the embryo is created after the sperm and egg are fertilized, whereas an egg is retrieved from the ovary and frozen prior to fertilization.
Freezing eggs gives you the opportunity to fertilize those eggs in the future, either from a partner or sperm donor of your choosing when you are ready. It allows for improved pregnancy success rates even in your later reproductive years because the eggs being used are of a younger age (thus of better quality).
Although egg freezing is a great option, the quality of those eggs cannot be determined until the eggs are fertilized and embryos are created. In some cases, when women return to thaw their previously frozen eggs and create embryos, the outcome might not be what they were expecting.
The alternative option, fertilizing the eggs after retrieval and creating embryos—gives us more information about the quality of the eggs. We can assess how many of the eggs fertilize and how many of those continue to grow and divide to become more developed embryos (blastocysts). The additional option of undergoing PGT-A to assess which embryos are chromosomally normal, gives information about which of the eggs have the ability to lead to embryos that have the ability to lead to healthy live births. Additionally, although the outcomes using frozen eggs are good, they are not always equal to that of fresh eggs (when they are fertilized immediately after egg retrieval and embryos are created).
These reasons are why many women (even single ones) opt to create embryos instead of just freezing eggs (either using sperm from a partner/significant other or donor sperm). The ability to know how many of their eggs led to embryos, and the number of those embryos that are chromosomally normal, provides a lot more reassurance (some might even choose to use the word “insurance”) than the unknown that comes with frozen eggs.
Although creating embryos may offer better outcomes and more information—it may not be the right option for you. In many cases, I often refer patients to meet with one of our counselors/therapists that specialize in counseling patients undergoing fertility treatments, particularly third party reproduction, to get a broader view of how this decision may impact your life in the future. For some patients, depending on the anticipated number of eggs being retrieved—we discuss the options of fertilizing half the eggs while freezing half, providing patients with both options during the same cycle. As with any decision, the pros and cons of this decision should be discussed but for many it is a viable option.
Anyone considering moving forward with a fertility preservation cycle should make sure they are aware of all of their options, and how these varying options have differing success rates prior to making a treatment plan. An open dialogue and a full understanding of how each treatment avenue differs is pivotal when making these important decisions.