How to Interpret IVF Success Rates Reported by Thai Clinics

When a Thai clinic reports an IVF success rate, the number usually describes one specific outcome in one specific group of patients. It is not a personal prediction. Two clinics can both report honestly and still show very different figures, because they may count different things: a positive pregnancy test, a clinical pregnancy seen on ultrasound, or a live birth. They may also calculate the rate per started cycle, per egg collection, or per embryo transfer. Before you compare any numbers, ask what is being counted, in whom, and over what period.

At a glance

• “Success” can mean a positive test, a clinical pregnancy, or a live birth. These are not the same.
• Per-cycle and per-transfer rates answer different questions and are not interchangeable.
• Age, ovarian reserve, embryo stage, and whether PGT-A was used all change the expected range.
• A single headline number rarely tells you how a clinic handles your specific situation.
• Ask how the clinic defines, calculates, and reports its figures before drawing conclusions.

Why the same word can mean different things

In fertility care, “success” is a broad term. A clinic might report any of the following:

• Positive pregnancy test: a blood test showing the pregnancy hormone hCG is present. This can occur without a continuing pregnancy.
• Clinical pregnancy: a pregnancy confirmed by ultrasound, usually by seeing a gestational sac, and sometimes a heartbeat.
• Ongoing pregnancy: a pregnancy that continues beyond a certain point in early development.
• Live birth: the birth of a living child. This is often considered the most meaningful outcome for patients, but it takes longer to measure and is reported less often.

If one clinic reports clinical pregnancy and another reports live birth, the second number will usually be lower even if the underlying care is similar. That does not automatically make one clinic better or worse. It means you are looking at two different measures.

Per cycle, per transfer, or per patient?

The denominator matters as much as the outcome. Common ways to report include:

• Per started cycle: everyone who began stimulation is included, even if the cycle was cancelled before transfer.
• Per egg collection: only cycles that reached the retrieval stage are included.
• Per embryo transfer: only cycles that reached transfer are included. This often produces the highest number, because it excludes cycles that stopped earlier.
• Per patient: a person may have more than one cycle, so this can differ from per-cycle reporting.

A high per-transfer rate can coexist with a lower per-cycle rate at the same clinic. Neither is dishonest, but they answer different questions. If you are trying to understand your chance of taking a baby home from a full treatment attempt, per-cycle or per-patient live birth figures are usually more relevant than per-transfer pregnancy figures.

What changes the expected range

Success rates are not a fixed property of a clinic. They reflect the patients treated as much as the care provided. Factors that commonly affect outcomes include:

• Female age: the single most consistent factor influencing egg quality and outcome.
• Ovarian reserve: how many eggs are available to collect.
• Cause of infertility: some diagnoses have different expected responses.
• Embryo stage at transfer: day-3 cleavage-stage and day-5/6 blastocyst transfers are often reported separately.
• Whether PGT-A was used: preimplantation genetic testing for aneuploidy can change which embryos are transferred and how results are counted.
• Number of embryos transferred: transferring more than one embryo can raise pregnancy rates but also raises the chance of multiples and associated risks.
• Previous IVF attempts: first-cycle and repeat-cycle patients are different groups.

Because of these variables, a clinic’s overall rate may not describe your likely experience. A clinic that treats many older patients or complex cases may report lower numbers than a clinic that treats mostly younger patients with a favourable prognosis, even if both provide good care.

PGT-A and how it affects reported rates

PGT-A (preimplantation genetic testing for aneuploidy) is sometimes used to select embryos for transfer. When clinics report success rates, it helps to know:

• Whether the rate includes only PGT-A-tested transfers or all transfers.
• Whether embryos with no result or inconclusive results are counted, and how.
• Whether the clinic reports outcomes per transfer, per tested embryo, or per cycle.
• How many embryos were available and how many were suitable for transfer after testing.

PGT-A can change the number of embryos available for transfer, so a clinic’s PGT-A-related figures may not be comparable to its non-PGT-A figures. Ask for the definitions rather than assuming the numbers mean the same thing.

Why direct comparisons between clinics are risky

Comparing a headline number from one Thai clinic with a headline number from another is rarely a like-for-like exercise. Differences may come from:

• Different definitions of success.
• Different denominators (per cycle, per transfer, per patient).
• Different patient populations, including age and complexity.
• Different time periods, since rates can change year to year.
• Different policies on cancelling cycles, transferring embryos, or using add-on treatments.

A higher number does not automatically mean better care for you. A lower number does not automatically mean worse care. The useful question is whether the clinic can explain its figures clearly and whether its approach fits your medical situation.

Questions to ask a clinic about its success rates

You can ask these questions by email or during a consultation. Clear, specific answers are a good sign that a clinic tracks its outcomes carefully.

1. What exactly does your reported success rate measure: positive test, clinical pregnancy, ongoing pregnancy, or live birth?
2. Is the rate calculated per started cycle, per egg collection, per transfer, or per patient?
3. Does the rate include all patients, or only certain groups such as those under a certain age or with a certain diagnosis?
4. How do you report outcomes for patients in my age range and with my medical history?
5. Do you report live birth rates, and if so, over what time period?
6. How do you count cycles that are cancelled before transfer?
7. How do you count PGT-A cycles compared with non-PGT-A cycles?
8. How many embryos are typically transferred, and how do you decide?
9. Do you report multiple pregnancy rates alongside success rates?
10. Can you explain your figures in plain language, including any limitations?

A short checklist before you compare numbers

• Write down the exact definition behind each number you see.
• Check whether the denominator is per cycle, per transfer, or per patient.
• Ask whether the figures apply to patients like you.
• Look for live birth data, not only pregnancy data.
• Ask about multiple pregnancy rates and how they are managed.
• Treat any single number as one piece of information, not a verdict.
• Discuss your personal situation with a qualified clinician rather than relying on averages.

What success rates cannot tell you

Success rates cannot tell you whether you will become pregnant, whether a particular treatment is right for you, or what your experience at a clinic will be like. They also cannot capture the quality of communication, the handling of complications, or the support you receive during a difficult process. Use them as a starting point for questions, not as a final answer.

Where to go next

If you are still at the research stage, it can help to read a broader overview of how success rates are discussed in Thailand, review common patient questions, and work through a structured guide before you contact a clinic. You can also reach out directly with your specific situation so that the next step is based on your needs rather than a headline figure.

Continue with our IVF success rates in Thailand overview, browse the FAQ, read our guides, or contact us with your questions.

Frequently asked questions

What is the difference between a clinical pregnancy rate and a live birth rate?

A clinical pregnancy rate counts pregnancies confirmed by ultrasound, usually by seeing a gestational sac or heartbeat. A live birth rate counts the birth of a living child. Live birth rates are usually lower than clinical pregnancy rates because not every clinical pregnancy continues to birth. When comparing clinics, check which measure is being reported.

Why do some Thai clinics report higher success rates than others?

Differences can come from how success is defined, whether the rate is per cycle or per transfer, the age and medical profile of patients treated, the time period covered, and how cancelled cycles or PGT-A cycles are counted. A higher number does not automatically mean better care for your situation. Ask each clinic to explain its definitions and patient group.

Should I choose a clinic based only on its reported success rate?

A single success-rate number is not enough to choose a clinic. It does not account for your age, diagnosis, or treatment history, and it cannot reflect communication, support, or how complications are handled. Use reported rates as one factor, ask detailed questions, and discuss your personal situation with a qualified clinician.

How does PGT-A affect reported success rates?

PGT-A can change how many embryos are available for transfer and how outcomes are counted. A clinic may report PGT-A and non-PGT-A cycles separately, or combine them. Ask whether the rate you are shown includes PGT-A cycles, how inconclusive results are handled, and whether the rate is per transfer, per tested embryo, or per cycle.

What questions should I ask a clinic about its success rates?

Ask what the rate measures (positive test, clinical pregnancy, ongoing pregnancy, or live birth), whether it is per cycle, per transfer, or per patient, which patients are included, how cancelled cycles are counted, how PGT-A cycles are reported, and whether live birth and multiple pregnancy rates are available. Clear answers help you interpret the numbers more accurately.

Continue your research

• How to interpret IVF success rates
• Frequently asked questions
• PGT and IVF guides

Medical information notice: This article is educational and does not replace individual assessment, diagnosis, genetic counselling or treatment advice from a licensed clinician. Provider services, availability, fees and policies should be verified directly before booking.