The Single Most Important Caveat
No fertility treatment — at any clinic, in any country — can guarantee pregnancy or live birth. Statistics describe groups of patients. They cannot predict any individual outcome. Specialists use statistics alongside your specific evaluation to discuss reasonable expectations.
Common Metrics You'll See
- Pregnancy rate per cycle — the proportion of cycles resulting in a confirmed pregnancy. Includes pregnancies that may later end in miscarriage.
- Live birth rate per cycle started — generally considered more meaningful; includes cycles that did not reach retrieval or transfer.
- Live birth rate per transfer — only counts cycles that reached embryo transfer; can look higher than per-cycle rates.
- Cumulative live birth rate — across one egg retrieval and all resulting transfers (fresh and frozen). Increasingly considered the most informative metric for IVF.
- Implantation rate — proportion of transferred embryos that implant. A laboratory and protocol indicator, not a direct patient outcome.
Why Age Stratification Matters
Outcomes vary substantially by age, particularly for own-egg cycles. A clinic-wide average can be misleading because it depends on the age distribution of the clinic's patient population. Reputable reporting stratifies outcomes by age band.
Diagnosis and Patient Mix
Clinics that treat more complex cases (e.g., advanced age, severe male factor, diminished ovarian reserve) may report lower headline rates while still providing excellent care. Compare clinics within the same patient subgroup, not just across overall averages.
Donor vs Own-Egg Cycles
Donor egg outcomes follow the donor's age profile and tend to differ statistically from own-egg outcomes. Reporting that combines both can be misleading.
Add-Ons and PGT-A
Adding preimplantation genetic testing or other technologies changes the population transferred. This can shift per-transfer success rates while having different effects on cumulative outcomes. Ask how a clinic accounts for this.
Questions to Ask About Statistics
- Are these per-cycle, per-transfer, or cumulative live birth rates?
- Are they stratified by age and diagnosis?
- Do they separate own-egg from donor-egg cycles?
- What is the time period of the data?
- How does this clinic's patient mix compare to mine?
The Bottom Line
Statistics are a tool for setting realistic expectations, not a promise. Decisions about treatment should be made with a qualified specialist who considers your full evaluation, values, and tolerance for the financial and emotional realities of treatment.