Your estimate
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Your estimated chances
Chances by number of eggs frozen
How the model-estimated chance grows as you bank more eggs at your age.
| Mature eggs frozen | ≥1 live birth | ≥2 live births |
|---|
How the model works
Each mature frozen egg is treated as an independent trial with a per-egg live-birth efficiency p that depends on your age at freezing; N is the number of mature eggs frozen. The chance of at least two live births subtracts the binomial "exactly zero" and "exactly one" cases. This is the same independence assumption used by Goldman et al. (2017) in their published counseling model.
Per-egg efficiency p by age at freezing
| Age at freezing | p (per mature egg) | Calibrated from |
|---|---|---|
| Under 35 | 8.5% | Doyle 2016: 30–34 y, 14 eggs → 70%; 10 eggs → ~60% |
| 35–37 | 7.7% | Doyle 2016: 15 eggs → 70%; age 35, 20 eggs → 80% |
| 38–40 | 4.5% | Doyle 2016: 26 eggs → 70%; age 38, 20 eggs → 60% |
| 41–42 | 2.3% | Goldman 2017: age 42, 61 eggs → 75%; 20 eggs → 37% |
| 43–44 | 1.1% | Doyle 2016: observed oocyte efficiency at 43–44 |
| 45 and over | 0.5% | Extrapolated — published data is very thin here |
Assumptions & limitations
- Population averages. The numbers come from published clinic cohorts (Doyle 2016: 128 autologous thaw cycles; Goldman 2017: 520 ICSI cycles modeled). Your clinic's thaw-survival and lab results may differ — ask for their age-specific numbers.
- Mature (MII) vitrified eggs. Immature eggs are not counted; the model assumes vitrification (modern flash-freezing), not slow-freezing.
- Independence is a simplification. Real outcomes within one person can be correlated (e.g., an underlying egg-quality factor). The model is a counseling aid, not a biological simulation.
- It says nothing about when you use the eggs. Only your age at freezing drives the estimate — that is the point of freezing.
- Not medical advice. Fertility decisions deserve a real consultation. Bring these numbers as questions, not answers.
Sources
- Doyle JO et al. "Successful elective and medically indicated oocyte vitrification and warming for autologous in vitro fertilization, with predicted birth probabilities for fertility preservation according to number of cryopreserved oocytes and age at retrieval." Fertility and Sterility 2016;105(2):459–466.e2.
- Goldman RH et al. "Predicting the likelihood of live birth for elective oocyte cryopreservation: a counseling tool for physicians and patients." Human Reproduction 2017;32(4):853–859.
Frequently asked questions
It uses the binomial model P = 1 minus (1 minus p)^N, where N is your number of mature frozen eggs and p is the per-egg live-birth efficiency for your age at freezing. The chance of at least two live births subtracts the binomial exactly-zero and exactly-one cases. The p values are calibrated from two peer-reviewed studies: Doyle et al. 2016 (Fertility and Sterility) and Goldman et al. 2017 (Human Reproduction).
The model uses 8.5% per mature egg frozen under age 35, 7.7% at 35 to 37, 4.5% at 38 to 40, 2.3% at 41 to 42, and 1.1% at 43 to 44, calibrated from Doyle 2016 and Goldman 2017. At 45 and over the model uses 0.5%, which is extrapolated because published age-group data is very thin past 44.
At 35 the per-egg efficiency is 7.7%, so P = 1 minus (1 minus 0.077)^15 = 69.9% chance of at least one live birth, and 32.3% chance of at least two. That matches Doyle 2016, where 15 frozen eggs at 35 to 37 gave about a 70% predicted chance of one live birth.
About 21 mature eggs: the model estimates 81.4% with 21, while 20 gives 79.9%, just under the target. For a 50% target at 35, about 9 eggs suffice (model: 51.4%).
Take age 38 with 20 mature eggs frozen: the model estimates 60.2% for at least one live birth but only 22.7% for at least two. A second child needs substantially more eggs, which is why the calculator shows both numbers.
Because per-egg efficiency falls steeply with age. With 20 frozen eggs the model estimates 83.1% at age 30 but only 37.2% at age 42. That is why freezing younger usually means fewer eggs needed for the same chance.
They always help, but with diminishing returns. At 35 the model estimates 33.0% with 5 eggs, 69.9% with 15, and 91.0% with 30. Going from 15 to 30 eggs buys about 21 extra percentage points, while the first 15 bought 70. No number of eggs can ever reach 100%.
No. It is a statistical model built on published clinic cohorts, giving population-average estimates. Your outcome depends on your clinic's thaw-survival and success rates, egg quality, sperm factors, and health factors no model can see. Use it to prepare questions, then discuss your plan with a fertility specialist.
It assumes each mature vitrified egg is an independent trial with the same age-based efficiency, counts only mature (MII) eggs frozen with modern vitrification, and uses only your age at freezing. This independence assumption is the same one Goldman et al. 2017 used in their published counseling model.
The model can only speak to efficiency: freezing younger gives a higher per-egg chance, so fewer eggs are needed for the same estimated outcome. It cannot weigh cost, health, or whether you will ever use the eggs. That trade-off is personal and medical, and belongs in a conversation with a fertility specialist, not a calculator.