Researchers Followed 921 Patients Who Froze Their Eggs; Here’s What They Found

In the last few years, egg freezing has become a more and more popular option for people who want to preserve their fertility and/or delay their family-building. While the process of egg freezing has improved significantly in recent decades, there’s still some concern about whether egg freezing is worth it (especially with its hefty price tag) and what outcomes to expect if someone does end up using their eggs. There haven’t been a ton of studies and surveys that look into this but it’s important information to know as you consider your fertility options. In this article, we’ll explore the findings of one large study that looked at nearly 1,000 patients who froze their eggs and what happened with those eggs years down the line. 

The nuts and bolts

First off, let’s get the boring definitions out of the way. The first thing to know is what type of study this is, or how it was designed. In this case, a retrospective observational cohort study was performed. This means that researchers looked at a group of people who had been exposed to a particular treatment in the past (in this case, egg freezing) and then followed them over time to see what happened. Pretty simple, right? The main goal of this type of research is to understand more about the relationship between the treatment in question and the outcomes that the research team chooses to measure.

What they looked at

Now, let’s get into the specifics of what was being measured in this study. The primary goal here was to follow a cohort of patients who returned to use their frozen eggs and to see what their cycle outcomes were. So, researchers looked at the clinical experiences of 921 people who froze their eggs at a fertility center between 2006 and 2020. Anyone who froze their eggs for medical reasons was excluded. They gathered information about each patient’s background, the freezing and thawing of their eggs, and what happened when they tried to have a baby using those eggs. 

The main outcome the researchers wanted to measure was the live birth rate (LBR), which is a number that tells you the chances of an actual baby being born. In addition to that, they also collected information about each patient’s clinical pregnancy rate (CPR) as well as their CPR and LBR per embryo transfer. CPR is the number that tells you the chances of a documented pregnancy. Once these results were collected, they were then separated based on whether the patients were younger or older than 38.

What they learned

Ok, now onto the good stuff: the results! There were several key questions that this study gave us some answers to. Let’s break them down.  

• What percentage of people actually come back to use their frozen eggs? 68 of the 921 patients in this cohort (7.4%) returned to use their frozen eggs to create embryos for transfer. Interestingly, the patients who came back to use their frozen eggs were on average older (about 38 years old).  

• What percentage of the people who used their frozen eggs got pregnant and had a baby (i.e., CPR and LBR)? Almost one-third of patients who came back (32.4%) successfully achieved a live birth from their frozen egg, with 39 years old (at the time of freezing) being the upper limit of success. No patient who froze eggs at the age of 40 or over had a successful live birth from those eggs. 

• How does age at time of egg freezing and at time of transfer impact clinical outcomes? There was a trend towards lower CPR and LBR the older the person was at the time they froze their eggs–this makes sense given our understanding that fertility declines as we get older. Almost 40% of people who were less than 38 years old at the time of egg freezing had a live birth, compared to only 25% of patients who were 38 and over. While this difference wasn’t a statistically significant one, it’s still evidence that age matters. 

• How did outcomes compare between people who tried having a baby using their frozen eggs and people who do in vitro fertilization (IVF) at the same age with non-frozen eggs? Even though the people who go through egg freezing may not have an infertility diagnosis at the time of the freezing, the rate of success for these patients is on par with IVF success rates for infertile patients in the same age group.

Strengths and weaknesses

As interesting as all of this data is, it’s always important to consider what strengths and limitations a study has. This study had some notable strengths. It provides us with real-world data on how well frozen eggs work. This is much more useful than the mostly theoretical data that’s been published before. In addition, the outcomes were described for each egg freezing cycle and as a total success rate for each patient. This total success rate is the most helpful when it comes to advising patients on their own chances of having a baby. The study also looked at 14 years of data from a single large hospital that does a lot of IVF in the area. With that long of a time span, we’re able to get a good idea of how patients have been doing in this region during that time.

Now, onto the limitations. One big issue with this study is that of the 921 initial patients, there weren't many to analyze who actually returned to use their frozen eggs. It's not surprising, then,  that no statistically significant differences could be found in the outcomes between the under 38 and over 38 age groups. What does this mean? Basically, these results should be taken with a grain of salt. A much larger study is the next step to confirm these findings, but that would likely take several more years given the low use of frozen eggs and the time it takes for someone to use their eggs after freezing them. Despite the small number of patients, this study is still one of the larger ones when it comes to reporting what happens once frozen eggs are thawed and used.

In a nutshell…

So what should you, as a potential egg freezer, take away from this? Here are the major points to remember:

• Based on the LBR of 32.4% that this study reports, egg freezing is a great fertility preservation option when done at younger ages (<38 years old).
• Age at time of egg freezing affects success more than age at the time of transfer. This was shown by the fact that no patient who froze eggs at age 40 or over had a live birth from those eggs.
• Using frozen eggs results in ongoing pregnancy or a live birth at a rate that’s on par with IVF patients of the same age. 

• These results should all be taken with a grain of salt because of the small number of people who actually returned to use their frozen eggs. A much larger study needs to happen next to confirm these numbers.  

At the end of the day, egg freezing provides people with more options so that they can have more control over their fertility options later down the line. It’s not a guarantee, though, and it should not be treated as such. There are so many factors that impact a person’s fertility and whether or not egg freezing is a good option for them. Family planning is going to look different for every person so you need to do what’s right for you. When you’re ready, talking to a fertility specialist can help you make up your mind. 

In the meantime, Freeze by Co is here to help you every step of the way on that journey. Our Split program allows those who qualify to freeze their eggs for free! In a “Split” cycle, you donate half of the eggs retrieved to a family that’s trying to conceive and freeze the remaining half for yourself. Or, if you don’t want to donate, you can still participate in the Keep program, where you’re able to freeze your eggs and keep them all for yourself, on your timeline. In addition, you’ll have access to our online support community. This valuable resource lets you engage with other people freezing their eggs at the same time! 

Whatever you end up choosing for yourself, our team is here to guide you through it and keep your options open.