PGT success rates in Thailand are not a single, standard number. Clinics may calculate and report them differently, using different patient groups, time frames and definitions of success. That means a higher percentage does not automatically mean better care for your situation. When you see a success rate, treat it as a starting point for questions, not a promise. Ask what was measured, who was included, over what period, and whether the figure applies to patients like you. This article explains the main reporting limitations and gives you practical questions to ask.
At a glance
- Success rates depend on definitions, patient mix and reporting methods.
- A rate for one clinic may not be comparable to another because of different denominators.
- PGT adds its own layers: embryo testing, transfer decisions and the difference between tested embryos and live births.
- Ask about the specific patient group, time period and outcome measured.
- Use rates as one part of your decision, alongside clinical fit, communication and practical factors.
Why PGT success rates are difficult to compare
PGT, or preimplantation genetic testing, involves testing embryos for certain genetic conditions before transfer. Success can be described at several stages: how many eggs were retrieved, how many embryos developed, how many were suitable for testing, how many tested embryos were available for transfer, and whether a transfer led to a continuing pregnancy or live birth. A clinic might report any of these as a “success rate.” Without knowing which stage is being described, the number is hard to interpret.
Even when two clinics report the same stage, they may include different patients. Some clinics treat older patients or patients with previous failed cycles; others may see a broader or narrower group. If one clinic treats a group with a higher chance of success on average, its rate may look better without implying better care. This is why comparing rates across clinics is often unreliable.
What denominators mean and why they matter
The denominator is the group of patients or cycles used to calculate a rate. For example, a rate might be based on all started cycles, all egg retrieval cycles, all cycles that reached embryo transfer, or only cycles using tested embryos. Each choice changes the result.
If a clinic reports success per transfer, it may exclude cycles that did not reach transfer. That can make the rate look higher than a rate calculated per started cycle. Neither approach is necessarily wrong, but they answer different questions. When you ask about a success rate, ask: “What is the denominator?” and “Does this include all patients who started treatment, or only those who reached a certain stage?”
Common ways success can be defined
Clinics may use different endpoints. Here are some examples you might hear:
- Positive pregnancy test: a biochemical pregnancy, which does not always continue.
- Clinical pregnancy: a pregnancy seen on ultrasound, but not necessarily a live birth.
- Ongoing pregnancy: a pregnancy that has continued beyond a certain point.
- Live birth: the birth of a live child, often considered the most meaningful outcome for many patients.
- Embryo-related outcomes: such as the proportion of tested embryos that are suitable for transfer, or the proportion of transfers that result in a pregnancy.
Each definition tells a different part of the story. A clinic might report a high positive pregnancy test rate, but the live birth rate could be lower. Ask which definition is being used and whether it is based on your own situation.
Why PGT adds extra layers of uncertainty
PGT is not a single test. It can involve different techniques and may be used for different reasons, such as screening for chromosomal number or testing for a specific inherited condition. The success of a PGT cycle depends on many factors, including how many embryos are available for testing, whether testing provides a result, and whether a suitable embryo is available for transfer.
Some clinics may report success rates specifically for PGT cycles, while others may include PGT within broader IVF statistics. If the reporting is not separated, it can be hard to know how PGT itself affects the numbers. Also, PGT does not guarantee a pregnancy or a healthy child; it provides information that may help guide embryo selection in some cases.
Questions to ask a clinic about success data
When a clinic shares a success rate, you can ask questions to understand its basis. These questions are not about challenging the clinic; they help you interpret the information.
- What exactly does this success rate measure? (For example: positive pregnancy test, clinical pregnancy, ongoing pregnancy, or live birth.)
- What is the denominator? Does it include all started cycles, or only those that reached a certain stage?
- Over what time period was this data collected?
- Does this rate apply to patients with my age, medical history and reason for PGT?
- Is this rate specific to PGT cycles, or does it include non-PGT IVF cycles?
- How many patients or cycles are included in this figure?
- Are there any exclusions, such as patients who did not have embryos available for transfer?
- How does the clinic define a “successful” outcome for patients like me?
- Can you explain the main factors that might affect my own chance of success?
You can also ask whether the clinic participates in any external reporting or accreditation that reviews outcome data. If so, ask what that process involves. This can give you a sense of how transparent the clinic is about its results.
How to use success rates in your decision
Success rates are one piece of information, but they should not be the only factor. Consider also:
- Whether the clinic’s approach fits your medical needs and preferences.
- How clearly the clinic communicates about uncertainty and risks.
- What support is available for international patients, such as language assistance and coordination.
- The overall cost structure and what is included, which you should confirm directly with the clinic.
- Practical travel and timing considerations, which you should verify with the clinic and relevant authorities.
Remember that no clinic can guarantee a specific outcome. A rate describes a group, not your individual future. Your own chance depends on many personal factors that only your treating clinician can assess.
Next steps for your research
As you gather information, keep a list of the questions above and ask them consistently across clinics. This can help you compare not just numbers, but also how openly each clinic discusses them. You may also want to read more about IVF success rates in Thailand and explore our guides for broader planning. If you have specific questions about your situation, consider speaking with a qualified healthcare provider. For general inquiries, you can contact us.
Frequently asked questions
Can I directly compare PGT success rates between clinics in Thailand?
Usually not directly. Clinics may use different definitions of success, different denominators, and different patient groups. A higher number does not automatically mean better care for your situation. Ask each clinic what exactly is measured and who is included.
What is a denominator in a success rate?
The denominator is the group used to calculate the rate, such as all started cycles, all egg retrieval cycles, or only cycles that reached embryo transfer. Different denominators can produce very different percentages, so it is important to ask which one is used.
Does PGT improve success rates?
PGT can provide information about embryos, but it does not guarantee a pregnancy or a healthy child. Its role depends on your individual circumstances. Ask your treating clinician how PGT might affect your own plan and what outcomes are realistic to expect.
What should I ask if a clinic quotes a high success rate?
Ask what outcome is being measured (for example, positive pregnancy test versus live birth), what the denominator is, over what time period, and whether the data applies to patients like you. Also ask if the rate is specific to PGT cycles.
Are success rates regulated in Thailand?
Reporting requirements and oversight can vary. We cannot provide legal or regulatory conclusions here. You can ask the clinic directly about any external reporting or accreditation it participates in, and verify details with the relevant authorities if needed.
Continue your research
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.