IVF success rates are one of the most searched — and most misunderstood — numbers in fertility care. This guide explains what published national registry data (HFEA in the UK, SART/CDC in the US, and ESHRE in Europe) actually shows about live birth rates by age, why a “single cycle” number is very different from a “cumulative” number, and how to read clinic figures critically. The data below reflects general population outcomes from official registries — not a guarantee of any individual result. This page has been prepared to be reviewed by our clinical team for medical accuracy.
What does “IVF success rate” actually mean?
There is no single definition. A “success rate” can be measured as a clinical pregnancy or as a live birth (a baby born) — and it can be expressed per embryo transfer, per single treatment cycle, or cumulatively per egg retrieval (counting every fresh and frozen transfer from one stimulation). These produce very different numbers for the same patient. Throughout this page we focus on live birth rate, the outcome that matters most, and we always state which denominator a figure uses.
IVF live birth rates by age
Age at the time of egg retrieval is the single strongest predictor of IVF outcome, because both the number and the chromosomal quality of eggs decline with age. The tables below use published national registry data.
United States — per intended egg retrieval (cumulative), SART 2023
This is the most patient-relevant view: the chance that one egg retrieval eventually leads to a live birth, counting all fresh and frozen transfers from that retrieval within a year (own eggs).
| Age band | Live birth per egg retrieval (all transfers) | Live birth per first transfer |
|---|---|---|
| Under 35 | 53.2% | 39.4% |
| 35–37 | 39.9% | 31.0% |
| 38–40 | 26.2% | 21.3% |
| 41–42 | 13.2% | 11.3% |
| Over 42 | 4.1% | 3.7% |
Source: SART National Summary Report, reporting year 2023 (US), own eggs.
United Kingdom — per embryo transferred (single transfer), HFEA
| Age band | Live birth per embryo transferred |
|---|---|
| Under 35 | ~32–35% |
| 35–37 | ~25% |
| 38–39 | ~15% |
| 40–42 | ~9–10% |
| 43–44 | ~3–5% |
| Over 44 | ~2% |
Source: HFEA, UK fertility statistics (2022/2024), per embryo transferred, own eggs.
The cumulative difference matters
Because IVF often takes more than one attempt, cumulative rates over several cycles are meaningfully higher than a single transfer. HFEA data, for example, indicates cumulative live birth across three cycles of roughly 65% for patients under 35, ~54% at 35–37 and ~42% at 38–39. This is why comparing a clinic’s “per transfer” number against another clinic’s “per retrieval” or “cumulative” number is misleading — they are not the same measurement.
Factors that affect IVF success
Age and ovarian reserve
As shown above, age is the dominant factor. Ovarian reserve markers such as AMH (anti-Müllerian hormone) and antral follicle count help estimate how many eggs may be retrieved, though they predict egg quantity better than egg quality.
Embryo quality and genetic testing
Transferring a chromosomally normal embryo substantially improves the live birth rate. In SART 2023 data, for patients aged 38–40 the live birth rate was 11.6% after an untested embryo versus 25.7% after a PGT-A normal (euploid) embryo. PGT-A is not right for everyone and should be discussed individually.
Frozen vs fresh transfer
Modern vitrification (fast-freezing) has made frozen embryo transfer (FET) outcomes comparable to — and in many protocols equal to or better than — fresh transfer, while allowing a more physiological uterine environment. The best choice depends on the individual protocol and patient.
Lifestyle and general health
Body weight, smoking, alcohol, and uncontrolled medical conditions can each reduce success. These are among the few modifiable factors and are worth optimising before treatment.
Clinic and laboratory quality
Embryology laboratory standards, stimulation protocols and the experience of the clinical team all influence outcomes — but they cannot override the biology of age.
How to read IVF success rates (a transparency note)
Be cautious when comparing headline numbers between clinics:
- Check the denominator. “Per transfer”, “per cycle” and “per egg retrieval” give very different figures.
- Pregnancy is not birth. Clinical pregnancy rates are always higher than live birth rates.
- Patient mix matters. A clinic treating mostly younger patients, or excluding complex cases, will report higher averages — this is not necessarily better care.
- Own eggs vs donor eggs. Donor-egg outcomes are far higher and should never be blended into “own egg” headline rates.
- A national average is not your personal prognosis. Only an individual assessment can estimate your own realistic chances.
At UCARER we believe an honest, well-explained number builds more trust than an impressive one. We discuss your realistic, individualised outlook openly during consultation.
Our approach at UCARER
UCARER Women’s Health provides evidence-based, individualised fertility care with transparent counselling. Rather than publishing a headline “success rate,” our clinicians take the time to explain what the published registry data means for your specific situation — your age, ovarian reserve, history and goals — and to set realistic expectations before any treatment begins. To learn more about the treatment process, see our IVF Treatment page, and for a transparent breakdown of fees, see IVF Cost in Turkey.
Ready for a clear, honest assessment of your own chances? Request a confidential consultation with our team. We will review your history, explain the relevant evidence, and outline a personalised plan — with no exaggerated promises, just transparent guidance.
Frequently Asked Questions
What is a good IVF success rate?
There is no single “good” number, because success rates depend on age, the measurement used (per transfer, per cycle, or cumulative per egg retrieval), and whether the figure counts pregnancies or live births. As a benchmark, national registries report a live birth per egg retrieval of around 53% for patients under 35, falling to about 26% at 38–40 and around 4% over 42 (SART, US, 2023, own eggs). A “good” rate is one honestly measured and explained for your individual situation.
How does age affect IVF success?
Age is the strongest single factor, because the number and chromosomal quality of eggs decline over time. UK HFEA data shows live birth per embryo transferred falling from roughly 32–35% under 35 to about 9–10% at 40–42 and around 2% over 44 (own eggs). This is why egg quality, not just quantity, drives outcomes.
Is the success rate for a single cycle the same as the cumulative rate?
No — and the difference is large. A single transfer gives a lower number than the cumulative chance across several attempts. HFEA data indicates cumulative live birth over three cycles of roughly 65% under 35, about 54% at 35–37 and around 42% at 38–39 — well above the per-transfer figures. Always check which one a clinic is quoting.
Does genetic testing of embryos (PGT-A) improve success?
It can improve the live birth rate per transfer by selecting a chromosomally normal embryo. In SART 2023 data, patients aged 38–40 had an 11.6% live birth rate after an untested embryo versus 25.7% after a PGT-A normal embryo. PGT-A is not appropriate for every patient and should be discussed individually.
Are frozen embryo transfers as successful as fresh transfers?
With modern vitrification, frozen embryo transfer outcomes are generally comparable to fresh transfer, and in many protocols equal or slightly better, partly because they allow a more natural uterine environment. The right choice depends on your individual protocol.
Why do different clinics report such different success rates?
Often because they measure differently (per transfer vs per retrieval vs cumulative), report pregnancy instead of live birth, treat different patient populations, or include donor-egg cycles in their headline numbers. This is why a clinic figure should never be taken at face value, and why an individual assessment matters more than an advertised average.
