Age is a crucial component of egg freezing because of three main issues: it impacts (1) the likelihood your eggs will work if you need them; (2) the number of cycles you’ll end up wanting to to do; and (3) the likelihood that you’ll ever need to use the eggs you froze.
One caveat: we use the words “younger” and “older” only in the context of a woman’s general window of fertility. “Younger” generally refers to women who are in their mid-30’s and younger, and “older” referring to women who are in their late 30’s and beyond. We realize that the fertility field is probably the only realm in which “older” would be used for that category.
Here’s the Catch-22 of egg freezing, as it applies to age specifically:
The younger you are, the more likely you’ll be to
The older you are, the more likely you’ll be to
Below is one study that illustrates this concept. A Spanish center broke down the live birth rates for women who froze their eggs and returned back to use them -- results are displayed based on the age at which a woman froze her eggs, and how many eggs she stored at the time.
This study has its flaws, but in our minds, it’s the best information we have available today. The study represents the largest sample of outcomes from women who chose to electively freeze their eggs. The shortcomings include: a small sample size (300 patients), the data is from a single center, and the age brackets (35 and younger vs. 36 and older) are crude. Thus, it’s hard to say how generalizable these observations are to all patients.
You’ll see that women who froze 10 eggs by the age of 35 had nearly double the rates of successful pregnancies compared with women who froze the same number of eggs at 36 or older.
What’s more, it becomes much less likely for “older” (age 36 and beyond) women to capture those 10 eggs in a single cycle, as evidenced by data below from a clinic in New York showing how many eggs were retrieved by age.
Thus, an advantage to freezing one’s eggs younger is that what she collects in each retrieval is more likely to be sufficient to lead a live birth.
Naturally, patients want to retrieve more eggs and, for this reason, many push their doctor to prescribe higher doses of hormones or to delay their retrieval another day. It’s unclear if these tactics increase the number of useful eggs (often only mature eggs can be frozen) and may well come with risks, namely over stimulating the woman into a state of OHSS (see our lesson on “The Risks of Egg Freezing”), or maturing the eggs too much.
According to the two largest studies available, women who froze their eggs have, so far, returned back to use them in only about 10% of cases.
Today our data tells us that the women who froze their eggs in their late 30’s have most frequently returned back to use their eggs, and they do so an average of two years after they were frozen. The belief is that these women had a strong sense they would need their eggs by the time they choose to bank. Thus, older women who freeze seem more likely to actually use their eggs.
How often do women who froze their eggs at younger ages return? For the moment, it seems far less often. The conventional wisdom is that these women may choose to freeze, then find a partner and manage to conceive naturally. But whether this is actually the case is unknown -- we need more time for these younger freezers to mature and to see if they return back at later ages to use their eggs. We simply haven’t been doing elective egg freezing for long enough to know the answer.
This is the principle reason that younger women are advised against doing egg freezing. However, you need to calibrate whether this is a sufficient reason not to freeze your eggs. Some women will freeze their eggs in the remote chances they are needed, and if they conceive naturally, are still pleased with the decision. Other women may be unhappy if they invested the time and money into egg freezing and ultimately never use their eggs.
Of course, there are some women who seem far more likely to ultimately need to use IVF, and are therefore more likely to eventually use and benefit from frozen eggs. This may become apparent even at a young age. This list includes women who have:
If you believe you’ll eventually need to do IVF, you’d far prefer to be doing it with younger eggs. Below is data on how women with younger eggs fare significantly better in the IVF process.