Why IVF Success Rates Can Be Misleading
When you start comparing IVF clinics in Thailand, success rates are often the first thing you look at. But those numbers can be presented in ways that make them look better than they really are. A clinic may report a high success rate for a specific group of patients, while the overall picture is different. Understanding how success rates are calculated and what they actually measure is essential to avoid being misled.
Success rates are not a simple score. They depend on many factors, including patient age, the cause of infertility, the type of treatment, and how the clinic defines a “success.” For example, some clinics count a pregnancy as a success, while others count a live birth. Some report success per embryo transfer, while others report per egg retrieval. These differences can make numbers hard to compare.
At a Glance: Key Points to Remember
- Success rates are not a guarantee of your outcome.
- Always ask how the clinic defines success and which patient group is included.
- Compare like with like: same age group, same treatment type, and same success definition.
- Look for live birth rates per cycle or per embryo transfer, not just pregnancy rates.
- Ask about the clinic’s reporting period and whether the data is audited.
How Success Rates Are Reported in Thailand
In Thailand, IVF clinics are not required to publish standardized success rates in the same way that some countries do. This means that each clinic may report its data differently. Some clinics may voluntarily follow international reporting guidelines, while others may not. Because there is no central registry, you need to be extra careful when comparing numbers.
Common ways clinics report success include:
- Clinical pregnancy rate per cycle started
- Clinical pregnancy rate per embryo transfer
- Live birth rate per cycle started
- Live birth rate per embryo transfer
- Cumulative live birth rate after multiple cycles
Each of these measures answers a different question. For example, the pregnancy rate per embryo transfer tells you the chance of a positive pregnancy test after a transfer, but it does not tell you if the baby was born. The live birth rate per cycle started is more meaningful because it includes all the steps from stimulation to birth.
Factors That Affect Success Rates
Success rates vary widely depending on patient characteristics. The most important factor is the age of the woman, especially the age of her eggs. Other factors include:
- Cause of infertility (e.g., male factor, tubal, endometriosis)
- Previous pregnancies or live births
- Number of previous IVF cycles
- Use of donor eggs or sperm
- Use of preimplantation genetic testing (PGT)
- Lifestyle factors such as smoking or BMI
When you compare clinics, make sure the success rates are for a group of patients similar to you. If you are 35 years old, a clinic’s success rate for women under 30 may not be relevant.
Questions to Ask a Clinic About Their Success Rates
To get a clear picture, ask the clinic directly. Here are some questions you can use:
- What is your live birth rate per cycle started for women in my age group?
- How do you define a live birth? Is it a baby born after 24 weeks of gestation?
- Do you include all cycles, or only those that reach embryo transfer?
- What time period does your data cover? Is it the most recent year?
- Is your data audited by an independent body?
- Do you report cumulative live birth rates after multiple cycles?
- How many cycles did you perform in that period?
These questions help you understand the context behind the numbers. A clinic with a high success rate but very few cycles may not be as reliable as a clinic with a slightly lower rate but many more cycles.
How to Use Success Rates Responsibly
Success rates are just one piece of the puzzle. They should not be the only factor in your decision. Consider other aspects such as:
- The clinic’s experience with your specific condition
- The qualifications of the medical team
- The laboratory standards and technology used
- The range of services offered, including genetic testing
- Patient support and communication
- Cost and value for money
Use success rates as a starting point for conversation, not as a definitive ranking. A clinic that is transparent about its data and willing to discuss limitations is often more trustworthy than one that only shows impressive numbers.
Understanding PGT and Its Impact on Success Rates
Preimplantation genetic testing (PGT) is sometimes used to screen embryos for chromosomal abnormalities before transfer. This can affect success rates in different ways. For example, if a clinic only transfers embryos that have been tested and found normal, the success rate per transfer may be higher, but the overall number of cycles may be lower because some embryos are not suitable for transfer.
PGT is not a guarantee of pregnancy or a healthy baby. It is a tool that can help select embryos, but it has limitations. Not all patients need PGT, and its use depends on your age, medical history, and the clinic’s recommendations. When comparing clinics, ask how they use PGT and whether their success rates include only tested embryos or all transfers.
Next Steps: Your Checklist for Comparing Clinics
- List the clinics you are considering.
- Ask each clinic for their success rates in a standardized format.
- Compare rates for your age group and treatment type.
- Ask about the definition of success and the reporting period.
- Look for independent audits or certifications.
- Consider the clinic’s overall experience and patient reviews.
- Schedule a consultation to discuss your specific situation.
Remember, the best clinic for you is not necessarily the one with the highest success rate. It is the one that offers personalized care, transparent information, and a treatment plan that fits your needs.
Frequently asked questions
What is the most reliable success rate to look at?
The live birth rate per cycle started is generally more reliable than pregnancy rates because it reflects the final outcome. However, it is still important to ask how the clinic defines a cycle and whether the data includes all patients or only a selected group.
Why do success rates vary so much between clinics?
Success rates vary because of differences in patient populations, treatment protocols, laboratory standards, and reporting methods. A clinic that treats older women or more complex cases may have lower success rates than a clinic that treats younger, healthier patients.
Can I trust success rates published on a clinic's website?
You can use them as a starting point, but you should ask for more details. Check if the data is recent, audited, and includes a clear definition of success. Be cautious of rates that seem unusually high without explanation.
Does PGT improve IVF success rates?
PGT can help select embryos that are more likely to implant, which may increase the success rate per transfer. However, it does not guarantee pregnancy or a healthy baby, and it may not be necessary for everyone. Discuss with your doctor whether PGT is right for you.
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.