Egg Calculator - Spring Fertility

Egg Freezing Outcome Estimator

Your Frozen Egg to Baby Probability Calculator

A transparent look at your chance of success with your frozen eggs

Freezing your eggs can be a valuable tool for creating options and improving your chances of having a healthy baby, but although often beneficial, it’s not a guarantee.

We created the Egg Freezing Calculator to help you develop realistic expectations around egg freezing, and to estimate your chance of having a healthy baby with your frozen eggs. The biggest factors in your success will be your age when you froze your eggs, the number of eggs you have frozen, and the experience and skill of your clinical and lab teams.

What are my chances? 1 Frozen Egg 2 Frozen Eggs 3 Frozen Eggs 4 Frozen Eggs 5 Frozen Eggs 6 Frozen Eggs 7 Frozen Eggs 8 Frozen Eggs 9 Frozen Eggs 10 Frozen Eggs 11 Frozen Eggs 12 Frozen Eggs 13 Frozen Eggs 14 Frozen Eggs 15 Frozen Eggs 16 Frozen Eggs 17 Frozen Eggs 18 Frozen Eggs 19 Frozen Eggs 20 Frozen Eggs 21 Frozen Eggs 22 Frozen Eggs 23 Frozen Eggs 24 Frozen Eggs 25 Frozen Eggs 26 Frozen Eggs 27 Frozen Eggs 28 Frozen Eggs 29 Frozen Eggs 30 Frozen Eggs 31 Frozen Eggs 32 Frozen Eggs 33 Frozen Eggs 34 Frozen Eggs 35 Frozen Eggs 36 Frozen Eggs 37 Frozen Eggs 38 Frozen Eggs 39 Frozen Eggs 40 Frozen Eggs 41 Frozen Eggs 42 Frozen Eggs 43 Frozen Eggs 44 Frozen Eggs 45 Frozen Eggs 46 Frozen Eggs 47 Frozen Eggs 48 Frozen Eggs 49 Frozen Eggs 50 Frozen Eggs 51 Frozen Eggs 52 Frozen Eggs 53 Frozen Eggs 54 Frozen Eggs 55 Frozen Eggs 56 Frozen Eggs 57 Frozen Eggs 58 Frozen Eggs 59 Frozen Eggs 60 Frozen Eggs 61 Frozen Eggs 62 Frozen Eggs 63 Frozen Eggs 64 Frozen Eggs 65 Frozen Eggs 66 Frozen Eggs 67 Frozen Eggs 68 Frozen Eggs 69 Frozen Eggs 70 Frozen Eggs 71 Frozen Eggs 72 Frozen Eggs 73 Frozen Eggs 74 Frozen Eggs 75 Frozen Eggs 76 Frozen Eggs 77 Frozen Eggs 78 Frozen Eggs 79 Frozen Eggs 80 Frozen Eggs 81 Frozen Eggs 82 Frozen Eggs 83 Frozen Eggs 84 Frozen Eggs 85 Frozen Eggs 86 Frozen Eggs 87 Frozen Eggs 88 Frozen Eggs 89 Frozen Eggs 90 Frozen Eggs 91 Frozen Eggs 92 Frozen Eggs 93 Frozen Eggs 94 Frozen Eggs 95 Frozen Eggs 96 Frozen Eggs 97 Frozen Eggs 98 Frozen Eggs 99 Frozen Eggs 100 Frozen Eggs < 30 Years Old 30 Years Old 31 Years Old 32 Years Old 33 Years Old 34 Years Old 35 Years Old 36 Years Old 37 Years Old 38 Years Old 39 Years Old 40 Years Old 41 Years Old 42 Years Old *age at which eggs are frozen Calculate > EXPECTED OUTCOME Based on Three Published Data Sets AT LEAST 1 CHILD: 2 OR MORE CHILDREN: SPRING’s Estimated Results: (7,572 warmed eggs) AT LEAST 1 CHILD: 2 OR MORE CHILDREN: Doyle and Colleagues (1,283 warmed eggs) AT LEAST 1 CHILD: 2 OR MORE CHILDREN: Cobo and Colleagues (1,513 warmed eggs) AT LEAST 1 CHILD: 2 OR MORE CHILDREN: ×

Result Info

Data sources:

This Frozen Egg Probability Calculator uses data from two published studies, as well as data published by Spring Fertility.  As new data are made available, we will update our calculator regularly to better help you make informed decisions with the best and most recent evidence available.   NOTE: All three data sources come from centers with significant experience in egg freezing.  Egg freezing is arguably the most technically challenging procedure performed in the IVF lab and is still performed by hand.  Every lab has their own unique approaches, even when using the same protocol.  We suggest you speak with your IVF center to understand their unique:

1. Survival rate of warmed eggs.
2. Fertilization rate of both fresh and frozen eggs.
3. Progression rate from fertilized eggs to blastocyst stage embryos.
4. Probability that your embryos are chromosomally normal. While this depends primarily on age at which your eggs are ovulated, age-specific rates may also vary from practice to practice (and even physician to physician).
5. Live birth rate per chromosomally normal embryo.

By combining these data points, you can produce a realistic and IVF center-specific probability of having a baby.

Using this Probability Calculator.  We created this tool for patients who want to better understand the likelihood of having a baby from their frozen eggs. It is also intended to help women who are deciding if egg freezing is right for them. By adjusting your input numbers, you will be able to evaluate the potential benefit and limitations of freezing your eggs. It’s important for your physician to provide a reasonably accurate assessment of the number of mature (usable) eggs that you should expect after your initial fertility consult (this number is typically between 50-100% of your antral follicle count).

Our Commitment. We will continue to update and publish our internal data and we will update the published studies and data as more become available. For now, the consistency of the Cobo et al. and Doyle et al. studies provides a good indicator of chances for success, particularly among women freezing their eggs before their 38th birthday.

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Spring’s Estimated Results

The Spring Fertility data uses the same method as Study B (by Doyle and colleagues). However, since most of the blastocysts we transfer have been previously tested for number of chromosomes, we assess the likelihood of obtaining a “chromosomally normal” blastocyst, rather than simply an untested blastocyst.

At Spring Fertility, we update our numbers every quarter based on the available data. This data set is representative of eggs thawed by December 31, 2024.

1. First, we evaluate the chance that a frozen egg will make it to a blastocyst stage embryo after warming – currently 37%. These data include 7,572 warmed eggs. The critical inputs are below:
   1. Thaw survival rate:  92%
   2. Successfully warmed (viable) egg to blastocyst development rate (this number will depend on the fertilization rate and embryo development rate):  *We do note some differences in these two numbers based on age at the time eggs were frozen:
      • 37% of cryopreserved eggs “frozen” BEFORE a patient’s 35th birthday fertilize and develop to blastocyst.
      • 33% of cryopreserved eggs “frozen” BETWEEN a patient’s 35th birthday and 38th birthday fertilize and develop to blastocyst.
      • 27% of cryopreserved eggs “frozen” BETWEEN a patient’s 38th birthday and 41st birthday fertilize and develop to blastocyst.
      • 15% of cryopreserved eggs “frozen” AFTER a patient’s 41st birthday fertilize and develop to blastocyst
2. Next, we estimate the percentage of these resulting blastocyst embryos that will be chromosomally normal (euploid) based on a woman’s age at the time her eggs are frozen.

*Please keep in mind that these data vary from clinic to clinic and even physician to physician, so if you are not a Spring patient and are using this tool, we recommend that you inquire with your doctor/clinic to understand the rates that their patients experience.

3. Lastly, we input the live birth rate per transfer of a chromosomally normal embryo. This will depend on the success of your clinics cryopreservation and frozen embryo transfer protocols and implementation. This is not dependent on the age of the woman receiving the transferred embryo. At Spring this number is currently 67%.

Steps 2 and 3 can be eliminated and you can substitute the live birth rate per blastocyst if your center does not test many embryos before transferring them.

The resulting output from our data result in live birth rates per cryopreserved oocyte as follows:

Spring estimated live birth probability
Maternal Age (years)	N = embryo samples with results	Euploid Rate (%)	Spring estimated efficiency*
<30	204	68.00%	16.9%
30	89	67.00%	16.66%
31	149	66.00%	16.4%
32	158	64.00%	15.9%
33	173	64.00%	15.9%
34	267	63.00%	15.6%
35	366	61.00%	13.5%
36	260	55.00%	12.2%
37	212	52.00%	11.5%
38	208	46.00%	8.3%
39	124	41.00%	7.4%
40	51	41.00%	7.4%
>41	27	40.00%	4%

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Study B: Doyle and Colleagues’ Results

Doyle and colleagues have reported the next largest data set to date, including live birth rates after warming 1,283 vitrified and subsequently warmed eggs between 2009 and 2015. This is one of the largest published data sets available. While not every embryo created from these frozen eggs was transferred, the authors estimated the live birth rates as if every viable blastocyst stage embryo was transferred. As a proxy for older patients who had fewer embryos, they used their success rates from their IVF outcomes – they had previously demonstrated that blastocyst stage embryos from frozen eggs had at least as high a pregnancy and live birth rate as blastocyst stage embryos from women of the same age using fresh, never frozen eggs.  Their published outcomes involved the below calculations:

1. Calculate the number of live births from frozen eggs from women at various ages.
2. They still had embryos (blastocysts) remaining from the frozen eggs that were not transferred and refrozen, so they estimated how many of those frozen blastocyst embryos would result in a live birth based on their experience with blastocyst stage embryos frozen from women of the same age (at the time the eggs were retrieved). This estimate allowed them to approximate the efficiency per egg.
3. Since this number looked unrealistically high for women at age 41-42, they substituted the efficinecy of live birth per fresh oocyte at this age and applied this number to the eggs that survived freezing/warming.

This study lacked extensive data on eggs frozen from women who are older than 37 (only 96 eggs).  The 96 warmed eggs from women over age 37 yielded 5 babies. These numbers gave an unusually high efficiency for women over age 37 so the authors correctly adjusted their data to “predict” the efficiency using:

1. Their survival rate for frozen eggs.
2. The anticipated number of blastocysts that would develop from those eggs.
3. Their live birth rates using blastocysts derived from fresh (non-frozen eggs) at each age group.

They then assumed a binomial “normal” distribution to yield the predicted probability per frozen oocyte at each age group. Our calculator uses the same assumption (a binomial distribution) to arrive at the probability of 1 or multiple children based on the number of eggs and the probability of a live birth per egg.

They arrived at the following estimates for live birth efficiency per egg:

Doyle et al 1,283 warmed eggs
<30	8.2%
<35	8.0%
35-37	7.3%
38-40	4.5%
41-42	2.5%

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Study A: Cobo and Colleagues’ Results

Cobo and colleagues is the largest data set of published outcomes from frozen/warmed oocytes. This study simply reported on the live birth rate per warmed egg in women of each age group.  We entered these estimates into a binomial calculator to arrive at the chances of having 1 or multiple live births based on the number of eggs used in each age group.

Interesting additional information:  the majority of these eggs were not tested for chromosome number. This study further reports no difference in outcomes based on amount of time samples were frozen (up to five years).  90.4% of warmed eggs survived the thaw and 1.4% of warming cycles had no eggs survive. These data yielded the following outcomes (the number of eggs included is represented on the right column).

Cobo and colleagues estimated efficiency (1,513 warmed eggs)		Number of eggs
< 35	6.6%	697
36-37	6.1%	312
38-39	5.6%	284
>40	1.8%	220

It is important to note that while this tool is based on the experience of our patients at Spring after warming approximately 7,572 frozen eggs, your success will be binary: an individual either achieves a successful pregnancy or not. Each individual’s fertility journey is affected by a number of factors, and each individual should work with their physician to predict the number of eggs they can expect to freeze, understand the likelihood of success at different ages, and use the provided estimates to assist in making the best decision for their future goals. This tool estimates the probability for a pregnancy based on Spring Fertility’s own egg freezing outcomes, which are updated regularly, as well as the two largest peer-reviewed published studies available.

What you need to know

How Your Probability is Calculated

Data from two published studies, as well as from our updated internal data, are used to provide an estimated live birth rate per frozen egg at each age. We then assume a normal (binomial) distribution of births among eggs to calculate the chances of having 1 and more than 1 child based on the number of eggs you have frozen and the age at which they were frozen. Click “Learn More” underneath each result to view the underlying data and to see how the estimates are calculated.

Our Commitment

We will continue to update and publish our internal data semiannually and we will update the published studies and data as more become available. For now, the consistency of the Cobo et al. and Doyle et al. studies provides a good indicator of chances for success, particularly among individuals freezing their eggs before their 38th birthday. For individuals over 37 years old at the time of freezing, data are still limited.

Award-Winning Research

Award-Winning Research: Clinical utilization and outcomes over eight consecutive years following oocyte cryopreservation

Spring Fertility’s, Dr. Gaya Murugappan was awarded the Private Practice Research Award at the 2023 Pacific Coast Reproductive Society’s Annual Meeting for her paper, “Clinical Utilization and Outcomes over Eight Years Following Oocyte Cryopreservation.” Dr. Murugappan’s research shows that while all individuals were able to achieve successful babies from frozen eggs, that after age 37, embryo development rates in frozen/thawed eggs decline more significantly than would be expected based on age alone. This indicates that there may be a structural component in eggs that begins to degrade after age 37, results in a decreased ability to fertilize and develop normally post-freeze/thaw. This doesn’t mean that egg freezing won’t work after age 37, but that the rate of decline becomes steeper at that age. It is important to speak with your fertility clinic about your individual chances of success based on their data and have an open conversation about how best to support your goals.

More About Egg Freezing

We hope that this tool will help you answer:

If I need to use my frozen eggs, how likely am I to have a child?

How many eggs do I need to freeze to feel comfortable?

Is this worth the cost (physically and economically) for me?

Want to speak more specifically about your fertility journey?

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