New research gives a better picture of egg freezing success rates after a single cycle
The Center for Fertility Research and Education (CFRE) was founded by Extend Fertility team members to close the fertility knowledge gap through sound scientific investigation.
Because of the investment required for egg freezing—even at affordable egg freezing practices like ours—many women are financially limited to a single cycle. It’s important, then, that any guidance we, or any provider, gives women includes the estimated number of eggs they’ll freeze in one cycle (based on age and AMH level), and the likelihood that they’ll be able to have a baby with those eggs later. Thus far, this kind of data has been scarce.
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In response to this gap, the research team at CFRE/Extend Fertility has published new research, “Probability of Attaining a 60% Age-Based Live Birth Rate (LBR) with the First Elective Oocyte Cryopreservation (EOC) Cycle.” This study is based on the results of over 1,100 egg freezing cycles performed at Extend Fertility between 2016 and 2018.
The researchers chose a 60% live birth rate (LBR) as the goal. As we know from other studies on egg freezing success rates, the chances of a live birth using frozen eggs are based on two factors: the woman’s age at the time of freezing and how many eggs she freezes. The higher a woman’s age, the more eggs she’ll need to freeze (due to a decline in egg quality with age). In order to get to a 60% LBR, women under 35 need to freeze 11 eggs, women 35–37 need to freeze 13, women 38–40 need to freeze 21, and women over 40 need to freeze 30.
At the same time that egg quality declines, egg count is declining, too. So while older women need to freeze more eggs, they typically freeze fewer eggs per cycle. This study quantified that. In our cohort, 60% of women under 35, 40% of women age 35–37, 9% of women 38–40, and just 2% of women over 40 were able to achieve their target number of frozen eggs within a single cycle. (Women under 35 froze, on average, 17 eggs, while women over 40 froze an average of only 9.)
Why is this important? First of all, it’s key that women have all the data they need to make an informed decision about egg freezing, including an individualized estimate of how many eggs they’ll be able to freeze each cycle and whether they will need more than one cycle to achieve their reproductive goals. And secondly, it provides a strong evidence base for the recommendation that women who are considering egg freezing freeze as early as possible to achieve better outcomes.
This research was recently presented at the ASRM Scientific Congress & Expo 2018 poster session. See the poster and more information about the research.