Medically reviewed by Dr. Arnab Kundu, MBBS, DGO, DNB (OBY-GYN), Infertility Specialist, IVF Expert and Gynaecologist at Renew Healthcare
In Brief
An IVF success rate means little until you know what it measures. Live birth per embryo transfer, compared within the same age group, is the most useful single figure when assessing an individual transfer. Clinical pregnancy rates are higher because they count pregnancies confirmed on ultrasound rather than babies born alive.
Cancelled cycles, frozen-embryo transfers and differences in patient age can also change the numbers. Before comparing clinics, ask how their success rates are calculated and which patients are included.
Why Can Two IVF Clinics Quote Very Different Success Rates?
You may see two IVF clinics reporting very different success rates for the same treatment. Both figures may be accurate because the clinics may be counting different outcomes, treating different patient groups or reporting results from different periods.
A percentage without its definition can be misleading. To compare clinics fairly, you need to understand what the rate measures, how many treatment cycles are included and whether the patients belong to a similar age group.
Three IVF Success Rates That Can Look Similar
There are three important measures to understand before comparing IVF clinic statistics.
| Measure | What it counts | What it tells you |
|---|---|---|
| Clinical pregnancy rate | Pregnancies confirmed on ultrasound | An early treatment outcome; it does not count babies born alive |
| Live birth per embryo transfer | Embryo transfers that result in a live birth | The outcome of an individual embryo transfer |
| Cumulative live birth rate | Live births from all included treatment cycles and frozen transfers over a defined period | A broader estimate of the chance of having a baby across treatment |
A pregnancy confirmed on ultrasound is not the same as a live birth. Some pregnancies end in miscarriage or are ectopic. This is why you should always ask which outcome a clinic is reporting.
How the Denominator Changes an IVF Success Rate
The denominator is the number used to calculate a percentage. Even when clinics report the same outcome, differences in the denominator can make their figures look very different.
1. Cancelled cycles
Some IVF cycles are cancelled before eggs are collected or before an embryo transfer takes place.
A clinic that calculates its success rate only from completed embryo transfers may report a higher percentage than a clinic that includes every cycle started. Neither figure can be interpreted properly without knowing which cycles were counted.
Ask whether the clinic's rate is calculated per embryo transfer, per egg collection or per cycle started.
2. Freeze-all policies
Some clinics freeze all suitable embryos and transfer them in a later cycle rather than transferring an embryo during the original stimulation cycle.
A per-transfer success rate does not include cycles that never reached transfer. This can make direct comparisons difficult.
The source material cites a Cochrane review reporting similar cumulative live-birth outcomes on average with freeze-all policies, alongside lower ovarian hyperstimulation syndrome (OHSS) risk and a higher risk of some pregnancy complications. These findings require careful interpretation and should be discussed with your treating specialist in the context of your own health and treatment response.
3. Different countries may use different definitions
National fertility registries do not always calculate success rates in the same way. Some figures may be based on embryo transfers, while others may use egg collections or another denominator.
Do not compare percentages from different countries or registries unless you understand their definitions and confirm that the measures are comparable.
Why Age Matters More Than a Clinic's Name
Age is one of the most important factors affecting IVF outcomes, particularly when a patient uses their own eggs.
The source document cites preliminary Human Fertilisation and Embryology Authority (HFEA) figures for 2024, published in June 2026. These figures report an average live-birth rate of 30% per embryo transferred using patients' own eggs, with a rate of 38% for patients aged 18–34 and 8% for patients aged 43–44. The source explicitly notes that the 2024 figures are preliminary and have not yet been validated.
The document also cites a 2015 cohort study reporting a first-cycle live-birth rate using own eggs of 12.3% for women aged 40–42, compared with 32.3% for women under 40. Its estimated cumulative live-birth rate over six cycles for women aged 40–42 was 31.5%. These are model-based estimates, not measured outcomes for every clinic.
These figures should not be used to predict your individual result. They illustrate why age groups must be compared like for like.
A clinic treating more patients over 40 may report a lower overall success rate while still providing appropriate care. A fair comparison uses the same age band, diagnosis, outcome definition and reporting period.
What National IVF Statistics Can and Cannot Tell You
National statistics provide context, but they cannot tell you exactly what will happen in your treatment.
Keep these points in mind:
National averages are not individual predictions. They combine results from different clinics, patient groups and diagnoses.
Cumulative estimates may depend on assumptions. The cited 2015 study used prognosis-adjusted estimates, which account for how patients who stopped treatment might have fared.
Recent figures may be preliminary. Fertility statistics can be published before the latest year's results have been fully validated.
Definitions matter. A percentage based on embryo transfers cannot automatically be compared with one based on egg collections.
Use national data to understand the broader picture, then ask the clinic for its own results with clear definitions.
Seven Questions to Ask Before Trusting an IVF Clinic's Success Rate
Before choosing a clinic, ask these seven questions and compare the answers side by side.
What does the percentage measure? Is it live birth per embryo transfer, per egg collection or per cycle started?
Are cancelled cycles included? Ask how the clinic accounts for cycles that do not reach egg collection or embryo transfer.
Are frozen-embryo transfers included? Ask whether fresh and frozen transfer outcomes are reported separately.
What are the results for my age group and diagnosis? An overall clinic average may not reflect your circumstances.
How many cycles are behind the percentage? A result based on a small number of cycles may be unstable.
Which years do the figures cover? Ask whether the figures are final, preliminary or still awaiting validation.
Can the clinic show cumulative live birth as well as per-transfer rates? These measures answer different questions and can provide complementary information.
A clinic's figures should be presented with their definitions, age groups, denominators, reporting periods and cycle counts. Do not assume that a headline percentage tells the whole story.
How Many IVF Cycles Should You Try?
There is no single number of IVF cycles that is right for everyone. Cumulative live-birth estimates can help explain how outcomes may add up over multiple cycles, but the chance in an individual cycle changes with age and other clinical factors.
Before treatment begins, agree on a review point with your doctor. After each cycle, discuss:
The number of embryos obtained and available for transfer.
Any reason the cycle was cancelled or did not reach transfer.
The cost and time involved.
Whether the treatment plan remains appropriate.
Whether additional cycles are likely to offer meaningful benefit.
Reassess the plan if your doctor believes further cycles are unlikely to help, the financial or time burden becomes unmanageable, or your health is at risk.
A clear, agreed review plan is more useful than following a fixed number of cycles without considering your circumstances.
Frequently Asked Questions
What is a good IVF success rate?
There is no single percentage that defines a good IVF success rate for every patient. Outcomes depend on age, diagnosis and the treatment outcome being measured. Compare live birth per embryo transfer with figures for the same age group, and ask for the definitions behind the numbers.
Is clinical pregnancy the same as live birth?
No. Clinical pregnancy means that a pregnancy has been confirmed on ultrasound. Live birth means a baby is born alive. Because some pregnancies do not result in a live birth, clinical pregnancy rates are higher and should not be treated as equivalent.
Why does age matter so much for IVF success?
Egg number and egg quality decline with age, which affects the chance of success when using one's own eggs. The source document's preliminary HFEA figures illustrate this difference across age groups. Ask your specialist to explain your prognosis using figures relevant to your age and circumstances.
Why do IVF clinics report different success rates for the same treatment?
They may count different outcomes, include different patient age groups, use different denominators or report results from different years. Cancelled cycles and frozen transfers may also be treated differently. Ask for definitions before comparing the percentages.
Does a freeze-all policy give a better IVF success rate?
Not necessarily. The Cochrane review cited in the source material found similar cumulative live-birth outcomes on average, alongside differences in OHSS and some pregnancy complications. Whether freeze-all is suitable depends on your treatment response, embryos and health.
How do I compare two IVF clinics fairly?
Use the same age group, outcome definition, reporting period and denominator. Ask whether cancelled cycles and frozen transfers are included, and how many cycles support each percentage. Put the same seven questions to both clinics before drawing a conclusion.
What if an IVF clinic does not publish its success rates?
Ask the clinic to provide its results by age group, with definitions, denominators, reporting periods and cycle counts. If it cannot or will not provide the information, consider that when deciding what questions remain unanswered. Do not choose a clinic based on an unexplained headline percentage alone.
The Bottom Line
An IVF success rate is useful only when you know what it counts. Live birth per embryo transfer, compared within the same age group and using the same definition, is a helpful measure for assessing an individual transfer. Cumulative live birth provides a broader view across treatment over a defined period.
Age matters, and clinic figures need context. Ask every clinic the same questions before relying on its success-rate table.
Ask About Success Rates With Clear Definitions
Dr. Arnab Kundu, Infertility Specialist, IVF Expert and Gynaecologist at Renew Healthcare, can discuss the questions you should ask when reviewing IVF outcomes.
Visit Dr. Arnab Kundu's profile or explore the Renew Healthcare website.
Bring your previous reports and the questions from this article to your consultation so that the figures and their definitions can be discussed in the context of your own situation.
This article is for general educational purposes and does not replace individual medical advice. Consult a qualified fertility specialist about your own circumstances.
References
Zaat T, et al. Freeze-all policies versus fresh embryo transfer. Cochrane Database of Systematic Reviews. 2021;2. Full title and DOI require verification before publication.
Human Fertilisation and Embryology Authority. Fertility Treatment 2024: Trends and Figures. London: HFEA; June 2026. Preliminary 2024 figures.
Smith ADAC, Tilling K, Nelson SM, Lawlor DA. Live-birth rate associated with repeat in vitro fertilization treatment cycles. JAMA. 2015;314(24):2654–2662. doi:10.1001/jama.2015.17296.