See your chance of at least one live birth from frozen eggs using retrieval age and mature egg count. You also get eggs typically needed at this age and target ranges for one or two children, with an option to estimate two live births.
How this calculator works
- Inputs: age at egg retrieval, number of mature eggs (MII), optional number of retrieval cycles, partner vs donor sperm, planned embryos per attempt.
- Outputs: chance of at least one live birth from your current eggs, optional chance of two live births, “eggs needed” for one live birth at this age, and suggested target egg ranges for one or two children.
Methodology & limits
Estimates are based on population averages for the steps from egg to live birth: thaw survival, fertilisation, development to transferable embryo, age-related chromosomal normality, and live birth per transfer. Age at retrieval drives most of the probability. MII eggs are summed across cycles. Partner vs donor sperm is used for context where severe male factor can reduce fertilisation; donor sperm is treated as no male-factor penalty.
“Eggs needed” is the approximate MII count at this age that gives about a 50–70% chance of one live birth with single embryo transfer, assuming average lab outcomes. Probability of two live births is estimated if you request it and if the egg count is likely to support two children.
This is an educational estimate only. Individual clinics, lab methods, and embryo testing choices can change outcomes. For personalised planning, speak with your clinician.
Frequently asked questions
What does MII mean?
MII are mature eggs that have completed meiosis I. Clinics report them because they are the eggs most likely to fertilise.
Why use age at retrieval?
Egg quality is tied to the age when eggs were collected, not the age at transfer. That is why the model uses retrieval age.
Does more retrieval cycles change the chance per egg?
No. The number of cycles does not change biology. The model sums your MII eggs across cycles and applies the same step-wise averages.
Does donor sperm improve success?
Donor sperm removes male-factor issues in the assumptions. If partner sperm has known issues, real-world fertilisation may be lower than average.
Is this a guarantee?
No. Results are estimates from population data and cannot predict individual outcomes. Discuss your plan with your clinician.