What Do IVF Success Rates Really Mean?
When you start researching IVF in Thailand, you will see success rates quoted by clinics, often as a percentage of cycles that result in a live birth. However, these numbers are not as straightforward as they seem. Success rates depend on many factors, including your age, the cause of infertility, the type of treatment, and how the clinic defines and reports its data. This guide helps you interpret these figures so you can compare clinics meaningfully and set realistic expectations.
Key Factors That Influence IVF Success
Age of the Female Partner
Age is one of the strongest predictors of IVF success. Generally, success rates decline as a woman ages, particularly after the mid-30s. This is due to a decrease in both the quantity and quality of eggs. When you look at clinic success rates, pay attention to the age groups they report. A clinic with a high overall success rate may have a younger patient population, which can skew the numbers.
Embryo Quality and Genetic Testing
Embryo quality is another critical factor. Many clinics now offer preimplantation genetic testing (PGT) to screen embryos for chromosomal abnormalities before transfer. While PGT can help select the most viable embryo, it does not guarantee pregnancy. Success rates for IVF with PGT may be reported differently than for IVF without PGT, so be sure to compare like with like.
Cause of Infertility
The reason for infertility also affects success rates. For example, couples with male factor infertility may have different outcomes than those with tubal blockage or unexplained infertility. Clinics may report success rates for specific diagnostic categories, but these are not always available.
How Clinics Report Success Rates
Clinics in Thailand, like elsewhere, may report success rates in several ways:
- Live birth rate per cycle started: This is the most meaningful measure, as it includes all cycles that begin, even if they are cancelled before egg retrieval.
- Live birth rate per embryo transfer: This only counts cycles that reach the point of embryo transfer, which can make the rate look higher.
- Clinical pregnancy rate: This is based on a positive pregnancy test or ultrasound, but not all clinical pregnancies result in a live birth.
Always ask the clinic which definition they use. The most honest and useful figure is the live birth rate per cycle started, broken down by age group.
Why Success Rates Vary Between Clinics
Even among reputable clinics, success rates can vary. Some reasons include:
- Patient selection: Clinics that accept older patients or those with complex medical histories may have lower success rates.
- Treatment protocols: Different clinics may use different medication protocols, which can affect outcomes.
- Laboratory standards: The quality of the embryology lab is crucial, but this is not always reflected in published rates.
- Reporting practices: Some clinics may exclude certain cycles from their statistics, such as those for patients with poor prognosis.
When comparing clinics, ask for their most recent annual report and check if it is audited by an independent body.
Questions to Ask a Clinic About Success Rates
To get a clear picture, ask the clinic directly:
- What is your live birth rate per cycle started for women in my age group?
- How do you define a cycle? Does it include cancelled cycles?
- Do you report success rates for patients using donor eggs or PGT separately?
- How many cycles did you perform last year? (A small number of cycles can make rates less reliable.)
- Do you have any independent verification of your success rates?
Limitations of Success Rate Data
Even with careful interpretation, success rate data has limitations. It is retrospective and may not reflect future outcomes. Also, success rates do not tell you about the quality of care, patient satisfaction, or the likelihood of complications. They are just one piece of the puzzle.
Using Success Rates in Your Decision
When choosing a clinic, consider success rates alongside other factors such as the clinic’s experience with international patients, the availability of genetic testing, the cost of treatment, and the support services offered. A clinic with a slightly lower success rate but a more transparent reporting policy may be a better choice than one with a higher number that is difficult to verify.
Next Steps
As you research, keep a checklist:
- Compare live birth rates per cycle started, not just pregnancy rates.
- Look for age-specific data.
- Ask about the clinic’s reporting methodology.
- Consider the full picture, including cost and services.
For more detailed information on IVF in Thailand, see our IVF success rates overview and PGT in Thailand guides. You can also explore our general guides and FAQ for additional insights.
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 started, broken down by the woman's age. This includes all cycles that begin, even if they are cancelled, giving a more realistic picture than pregnancy rates or rates per embryo transfer.
Why do IVF success rates vary so much between clinics?
Success rates vary due to differences in patient populations, treatment protocols, laboratory standards, and reporting practices. Some clinics may exclude certain cycles from their statistics, so it's important to ask how they define and report their data.
Does PGT improve IVF success rates?
PGT can help select embryos with the correct number of chromosomes, which may reduce the risk of miscarriage and increase the chance of a live birth per transfer. However, it does not guarantee success, and not all patients need PGT. Discuss with your doctor whether it is appropriate for you.
How should I compare success rates between clinics in Thailand?
Ask each clinic for their live birth rate per cycle started for your age group, and ensure they use the same definition. Also consider the number of cycles performed and whether the data is independently verified.
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.