Freezing eggs vs. freezing embryos—often confused—are in fact separate processes, each with their own pros and cons. The difference? Whether eggs are fertilized before or after they’re frozen and thawed, and whether you need to choose now or later who fertilizes those eggs.
Here, we’ll delve into freezing eggs vs. freezing embryos and help you decide which option is right for you.
The process of freezing eggs vs. freezing embryos
The egg freezing procedure and the embryo freezing procedure both start the same basic way: with hormone medication, injected over for 8–12 days, that stimulates the ovaries to produce multiple eggs. (Multiple eggs is important because not every egg will lead to a baby, no matter how young you are. Freezing multiple eggs increases the doctor’s chances of finding healthy eggs later. More eggs, more potential!)
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Learn more about the egg freezing process.
Once mature, the eggs are collected from the ovaries and flash frozen with liquid nitrogen, bringing them to a temperature so low that all activity within the cell—including aging—pauses, freezing them in time. As we age, the eggs inside our bodies age with us, and the likelihood that our eggs are healthy gets lower. By freezing eggs when you’re young, you can preserve their health.
If you choose to use these eggs to get pregnant later, they’ll be thawed in a lab and fertilized with sperm to create an embryo (a process known as in vitro fertilization or IVF). The good news is that, because the eggs were frozen in time, they’ll be just as young and healthy as they were at the time they were frozen.
The difference between freezing eggs vs. freezing embryos can be found in the lab, too. During embryo freezing, the eggs are fertilized using IVF before they’re frozen, and develop, over a period of several days, into embryos, which are then flash frozen. Once again, the health of the embryos, created from young and healthy eggs, is maintained when they’re frozen at such a low temperature.
Freezing eggs vs. freezing embryos: the differences
There was a time, using older slow freeze technology, when embryos survived the freezing and thawing process better than eggs, because embryos are slightly less delicate. However, the introduction of vitrification (flash freezing) has largely eliminated this difference. With this state-of-the-art technique, the survival rates when freezing eggs vs. freezing embryos are very similar: 90%+ of eggs and about 95% of embryos survive.
Many people also believe that a frozen embryo is more likely to “work”—AKA, become a pregnancy—than a frozen egg. But that’s not really a true comparison, statistically speaking. When comparing freezing eggs vs. freezing embryos, it typically requires several eggs to result in one embryo, no matter which method you choose. You can freeze many eggs, which may be fertilized later to create a few embryos; or, you can fertilize the eggs right after retrieval, and freeze the few embryos that develop. Either way, you will likely have the same number of potential chances at pregnancy.
Learn more about egg freezing success rates.
Freezing embryos does give you more information up front; namely, you’ll know how many eggs were healthy enough to fertilize and begin development. But it also locks you into at least one important decision right now: whose sperm will fertilize those eggs in the first place.
Why choose egg freezing vs. embryo freezing?
Simply put, when comparing freezing eggs vs. freezing embryos, egg freezing offers more options and simpler choices for many women. Embryo freezing, which requires sperm to fertilize the egg before freezing, just isn’t all that useful for single women, or women who aren’t sure that their current partner is the co-parent they’re looking for.
Freezing embryos with donor sperm means that, if you find a partner down the line and want to have biological children with them, you won’t be able to use your frozen embryos. And freezing embryos with your current male partner—even if you’re not sure you want to start a family with them—might mean you can’t use those embryos down the line with a new partner; or, in fact, could create legal issues with your former partner if one of you want to use or discard the embryos and the other does not.
When deciding between freezing eggs vs. freezing embryos, it’s important to remember: freezing eggs doesn’t require you to make co-parenting decisions right now (phew!). When you freeze your eggs, you can preserve your fertility independently, giving women what an article in the New England Journal of Medicine calls “reproductive autonomy.” And because studies tell us that women who are delaying childbearing are usually doing so because they haven’t met the right partner yet, it’s really important that fertility preservation result in more options later on—not fewer.
In fact, Dr. Owen Davis, president of the American Society for Reproductive Medicine, thinks that egg freezing should stay “on the table” even if he’s consulting with a couple, not just single women. The truth is that couples don’t always stay together. When comparing freezing eggs vs. freezing embryos, Dr. Davis argues, egg freezing offers a “simpler path forward during a breakup or divorce,” plus the option for “family planning with a future partner.”
Egg freezing also offers a simpler path forward if a woman or couple decides not to use their frozen materials. Because frozen embryos are, well, embryos, discarding them represents a complex moral dilemma for many women, and discarding embryos is disallowed in many faiths. Freezing unfertilized eggs, on the other hand, can make the decision to discard simpler—making the freezing eggs vs. freezing embryos choice clear.
Lastly, the upfront cost of egg freezing is less than that of embryo freezing, which requires in vitro fertilization before freezing. While egg freezing costs about $11,000 on average—and starts at under $7,500 here at Extend Fertility—the creation and freezing of embryos can add a few thousand dollars to that bill. And the smaller bill associated with freezing eggs vs. freezing embryos makes egg freezing an easier and more accessible choice, allowing more women to preserve their options for the future.
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