Typically, intending parents will need to decide whether they’d like their donor to have a retrieval (providing “fresh” eggs) or acquire eggs that have already been retrieved and frozen.
There is a lot of nuance to this discussion, and so we’ll try to step through this in a linear fashion. At times we’ll oversimplify the matter and bring up aspects that do not apply in all regions or to all patients.
Up until the early 2000s, nearly all egg donation was done using “fresh” eggs as the existing technology to freeze-and-thaw eggs (known as “slow freeze”) was deemed inferior. In the last 15–20 years, a newer freezing approach, known as “vitrification”, has raised the rates of success.
To illustrate, below is data from the HOPE study with over 16 fertility clinics contributing data. As you can see, more vitrified eggs survived the delicate thawing/warming process, and this translated into far higher success rates.
We highlight this for multiple reasons. First, some clinics globally still use the “slow freeze” process, and if you’re weighing whether to use frozen or fresh embryos, it’s important to ensure the eggs you're considering were frozen using vitrification.
Second, vitrification is a technique, not a standard, and so you’ll want to inquire whether the clinic that froze the eggs and the clinic that will warm them are both experienced. If an inexperienced clinic errs in freezing the eggs, it’s irrelevant how good the clinic is at warming the eggs. And vice versa. Again, the entities doing each of these steps must be competent. To learn more about this, see our dedicated course on IVF laboratories here.
Herein lies a risk in citing data with frozen donor eggs: many of the clinics providing data are experienced pioneers and what they report may not be generalizable to other clinics. When possible, we try and cite studies that report from multiple clinics unless we’re trying to illustrate a very specific point.
A next question is whether donor eggs that have been subject to vitrification are as effective as donor fresh eggs. The answers can be hard to nail down but in short, it would appear fresh eggs are slightly more effective.
To illustrate, let’s look at a Spanish study. You’ll see donors provided the same number of eggs, and after the freeze and thaw process on the vitrified eggs, the number of available eggs for the recipients was similar. Likewise, the percentage of cycles producing one “high quality” embryo was similar, and the pregnancy rates per cycle were extremely close. This reflects positively on vitrified eggs.
The major distinction appears to be that the fresh cycles tended to produce more total embryos, and thus, more excess embryos to be stored. As we’ll discuss, this can be an important datapoint depending on the number of children you want the option to have or your feelings about the possibility of creating embryos you’re unlikely to use.
In 2018, U.S. investigators published broader data from all clinics that seemed to reflect fresh donor egg cycles produced more embryos and produced higher success rates. This data reflects more positively for fresh eggs.
Sometimes frozen eggs are immediately available while the timeline to acquire fresh eggs can be longer: a donor will need to be medically and psychologically screened and find time to start the cycle. As a result, acquiring frozen eggs may save weeks or months and head off risk a donor changes her mind (which can be devastating to the intending parents) or has a surprisingly unproductive cycle.
While costs differ region to region, let’s suppose it costs a clinic $18,000 to recruit a donor and retrieve her eggs. Let’s say the donor produces 18 eggs.
In the circumstance of a fresh egg cycle, the intending parents pay the entirety of the $18,000 and keep all 18 eggs. Fairly simple.
In the circumstances of a frozen egg cycle, the clinic freezes the eggs, and in many countries, divides them into batches of three, selling each recipient a batch of 6 eggs for, say, $6,000.
Many point out acquiring frozen eggs is cheaper (e.g. in this example $6,000 vs $18,000), but on a per embryo basis, that’s likely not true, as you can see from the oversimplified, sample worksheet below.
For those who want more than one child, or who want to substantially mitigate the risk the cycle will fail, having more embryos is important and the value of fresh eggs is more pronounced.
For those who want just one child, and who are comfortable with the risk of having fewer embryos available to have that child, acquiring frozen eggs may be more compelling.
(We should note that many third parties that provide frozen eggs are prepared to provide a guarantee that some number of eggs will thaw or embryos will be created).
While there are myriad confounders in the decision, we believe the below breakdown of the trade-offs hold for many intending parents weighing the decision.