How to Interpret IVF Success Rates in Thailand Without Being Misled

When you compare IVF clinics in Thailand, success rates are often the first number you see. But those numbers can be presented in many different ways, and without careful reading, you may draw the wrong conclusions. This guide helps you understand what to look for, what questions to ask, and how to compare clinics fairly.

At a Glance: Key Points to Remember

• Success rates are not standardized across clinics, so direct comparisons can be misleading.
• Always look for age-stratified data, not just an overall average.
• Check whether the rates refer to fresh cycles, frozen cycles, or all cycles combined.
• Ask whether PGT-A (preimplantation genetic testing for aneuploidy) was included in the reported cycles.
• Understand the difference between pregnancy rate, live birth rate, and ongoing pregnancy rate.

Why IVF Success Rates Are Not Directly Comparable

IVF success rates depend on many factors, including patient age, cause of infertility, embryo quality, and clinic protocols. Because clinics may report different types of cycles, use different definitions of success, and treat different patient populations, a simple percentage cannot tell the whole story. For example, a clinic that treats mostly younger patients may report higher success rates than one that treats many older patients, even if the quality of care is similar.

Additionally, some clinics may report success per embryo transfer, while others report per egg retrieval. These are very different denominators. Always check what the rate is based on.

Key Questions to Ask About Any Success Rate

Before you trust a success rate, ask the clinic for the following details:

• What is the definition of success? Is it a positive pregnancy test, a clinical pregnancy (seen on ultrasound), or a live birth? Live birth rate is the most meaningful outcome.
• What is the age range of the patients included? Rates should be broken down by age groups, such as under 35, 35-37, 38-40, and over 40.
• Are fresh and frozen cycles reported separately? Frozen embryo transfers (FET) often have different success rates than fresh transfers.
• Were PGT-A tested embryos included? If a clinic reports success rates for PGT-A tested embryos, that is a different population than untested embryos.
• How many cycles were included? Small sample sizes can make rates unreliable.

Understanding Age-Stratified Data

Age is the single most important factor in IVF success. A clinic’s overall success rate may be skewed by the age profile of its patients. For example, if a clinic has a high proportion of patients under 35, the overall rate will be higher than a clinic that treats many patients over 40. Always ask for success rates broken down by age group. This allows you to compare clinics more fairly for your specific age.

Fresh vs. Frozen Cycles: Why It Matters

Some clinics report success rates for fresh embryo transfers, others for frozen embryo transfers, and some combine both. These can differ significantly. Frozen embryo transfers are now common, and in some cases, they may have higher success rates than fresh transfers, especially when the uterine lining is better prepared. When comparing clinics, make sure you are comparing the same type of cycle.

The Role of PGT-A in Success Rates

PGT-A (preimplantation genetic testing for aneuploidy) screens embryos for chromosomal abnormalities before transfer. When a clinic reports success rates for PGT-A tested embryos, it is reporting on a selected group of embryos that have already passed a screening step. This can lead to higher success rates per transfer, but it does not mean that PGT-A guarantees a pregnancy or a live birth. Also, not all patients choose PGT-A, and its use varies by clinic. When you see a success rate, ask whether PGT-A was used and whether the rate includes only tested embryos or all embryos.

Other Factors That Affect Success Rates

Beyond age and cycle type, other factors can influence success rates:

• Cause of infertility: Some diagnoses, such as severe male factor or diminished ovarian reserve, have lower success rates.
• Number of previous IVF attempts: Patients who have had multiple failed cycles may have lower success rates.
• Embryo transfer policy: Some clinics transfer multiple embryos, which can increase pregnancy rates but also increase the risk of multiples.
• Laboratory standards: Embryology lab quality can affect embryo development and survival.

Questions to Ask a Clinic

When you speak with a clinic, ask these specific questions:

• What is your live birth rate per egg retrieval for my age group?
• What is your live birth rate per frozen embryo transfer for my age group?
• Do you report success rates for PGT-A tested embryos separately?
• How many cycles were included in your reported rates?
• What is your policy on single vs. multiple embryo transfer?

Next Steps: How to Compare Clinics Fairly

1. Gather success rate data from several clinics, but always ask for the same type of data (e.g., live birth rate per frozen embryo transfer for women under 35).
2. Ask for age-stratified data and check if the sample size is adequate.
3. Ask whether PGT-A was used and whether the rates are for tested or untested embryos.
4. Consider other factors like clinic experience, lab standards, and your personal comfort.
5. Remember that success rates are just one part of the decision; your individual circumstances matter more.

By asking the right questions and understanding how success rates are calculated, you can make a more informed choice and avoid being misled by numbers that may not apply to you.

Frequently asked questions

What is the most reliable IVF success rate to look at?

The most reliable measure is the live birth rate per cycle or per embryo transfer, broken down by age group. This gives you a realistic picture of the chance of having a baby, not just a positive pregnancy test.

Why do IVF success rates vary so much between clinics?

Success rates vary because clinics report different types of cycles, use different definitions of success, and treat different patient populations. Without standardization, direct comparisons can be misleading.

Does PGT-A improve IVF success rates?

PGT-A can help select embryos that are more likely to implant, which may increase the success rate per transfer. However, it is not a guarantee, and its impact depends on individual factors. Always ask how PGT-A affects the reported rates.

Should I compare fresh and frozen embryo transfer success rates separately?

Yes, because fresh and frozen cycles can have different success rates. Comparing them separately gives you a clearer picture of what to expect for each type of transfer.

Continue your research

• How to interpret IVF success rates
• PGT in Thailand overview
• 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.