Our extensive work analyzing more than 4,000 egg freezing cycles revealed excellent thaw survival rates, pregnancy rates after an FET, and live births using frozen eggs.

Since 2016, Extend Fertility has been helping women take control of their reproductive futures. We were founded on the premise that egg freezing (also known as egg cryopreservation) should be both accessible and affordable for anyone who wants to be proactive about their fertility. And for just about as long as we’ve been in practice in New York  — that’s eight years and counting — we’ve been providing excellent care and marking individual success stories as we follow along on patients’ journeys from egg retrieval(s) to frozen embryo transfer (FET), often with years in between. Now, we’ve conducted a comprehensive, retrospective study, which confirms what we’ve known all along; egg freezing works.

Extend Fertility co-founder and chief clinical officer, Dr. Joshua Klein, along with Dr. Nataki Douglas, chief scientific officer, presented the groundbreaking research at the 2024 American Society of Reproductive Medicine (ASRM) Conference in Denver, CO. The goal of the study was twofold: to analyze success rates of those who returned to use their frozen eggs years later; and, secondarily, to improve patient counseling based on these findings.

Our expansive work confirms the excellent news that egg freezing is a game-changer for individuals who want to take control of their fertility and build a family on their own terms…and on their own timeline.

What’s the goal of the egg freezing study?

It’s known in our field of reproductive endocrinology that egg freezing is a great way to preserve fertility, which declines with age. A few studies have been done on the success rates of patients who went back to use their frozen eggs years later once they were ready to become parents, but none were from a single fertility center. So, our team set out to evaluate the results of these thaw cycles, looking at thaw survival rates, pregnancy rates after a frozen embryo transfer, and live births using frozen eggs. 

Check out Dr. Klein’s ASRM presentation:

We also wanted to use this research to help guide consults with prospective egg freezing patients, to essentially help each patient set realistic goals on their estimated live birth rate (which includes live births or pregnancies past 12 weeks).

How was the egg freezing study performed?

Over the course of eight years, 2016 to 2023, 3,142 patients underwent 4,665 egg freezing cycles at Extend Fertility in New York. 4,071 eggs were thawed in 271 thaw cycles. The research team then categorized the results by age; patients who did more than one egg freezing cycle were placed under the age category they were during their last cycle.

What are the results of the egg freezing study?

One of the key trends noted over the course of the study is that the average age of patients electively freezing their eggs was 37 in 2016, down to age 35 by 2023. This shift means women are taking control over their reproductive futures earlier in life (woohoo!).

The success rates for frozen eggs were encouraging too. The biggest takeaways:

• More than 90% of frozen eggs survived the thawing process, with an average freezing age of 36 years
• 50% of embryos created from the frozen eggs were genetically normal (euploid), which is a similar percentage of euploidy as fresh eggs
• Patients returned for their first transfer from thawed eggs at a mean age of 40 years
• The pregnancy success rate — defined by live births or pregnancies past 12 weeks — was more than 55% for patients across all age groups

“These findings highlight our practice’s expertise and underscore our commitment to delivering the best in fertility care,” says Nataki Douglas, MD, PHD, chief scientific officer of Extend Fertility. “Despite skepticism around egg freezing, this study proves it’s a reliable, science-backed option. It’s not for everyone, but for many, it’s life-changing and offers real outcomes.” 

How does the age at egg freezing affect pregnancy success rates?

As with all aspects of fertility, our study found that the patient’s age plays a factor in pregnancy success rates using frozen eggs. Not surprisingly, the younger the patient was at the time of her egg retrieval(s), the more euploid embryos she had available for transfer after genetic testing. 

Our study also found that pregnancy rates using frozen eggs decreased with age:

• 66.7% for 35 and under
• 56.8% for ages 35 – 37
• 45.7% for ages 38 – 40 years
• 33.3% at 41 – 42 years

Still, the promising news is that success rates are still higher for those who preserve their fertility at any age vs. those who try to get pregnant with fresh eggs as they get older.

What does this egg freezing study mean for me?

Our study confirms that egg freezing is a great way to take control of your reproductive future; freezing eggs now means it’ll be less difficult for you to start or grow your family than using eggs at the current age, because your eggs are younger. However, there are other factors that may make conception more difficult.

The ideal time to freeze eggs is before the age of 35; this age group generally has more genetically normal embryos available for transfer and higher pregnancy success rates, even for those patients whose first transfer was at age 40. 

Don’t let these stats discourage you if you’re older than 35. If you aren’t ready to pursue parenthood right now, freezing your eggs can still help make it easier for you down the line.

What is AMH and how does AMH affect egg freezing success rates?

AMH, or anti-Müllerian hormone, is a hormone secreted by the follicles in the ovaries. Generally speaking, the higher your level, the more follicles (potential eggs) you’re expected to have. 

Our study confirms that a higher AMH is correlated with more eggs retrieved per cycle. We plan to use this information to provide each of our egg freezing patients with a personalized expected live birth rate based both on their AMH and their age. You can go into the egg freezing process confident, and with realistic expectations.

Get in touch with Extend Fertility 

Ready to take control of your fertility? Learn more about egg freezing at Extend Fertility or reach out and ask us a question about our services. Extend Fertility has become one of the largest providers of egg freezing (cryopreservation) in the country, and we’d love to help you achieve your family building goals.