Questions to Ask When a Clinic Advertises an IVF Success Rate

Understanding the advertised number

When a clinic advertises an IVF success rate, the figure is usually a summary of past outcomes. But that single number can hide important details. Before you compare clinics or make decisions, it helps to understand what the number actually represents. This guide walks you through the key questions to ask so you can interpret the advertised rate in a meaningful way.

At a glance: what to check first

• What is the exact definition of success?
• What is the denominator (the group of patients included)?
• Is the rate broken down by age band?
• What is the time period of the data?
• Are the results from fresh or frozen embryo transfers?
• How many cycles were included?

Ask about the denominator

The denominator is the group of patients that the success rate is based on. A clinic might report success per egg retrieval, per embryo transfer, or per patient. Each denominator gives a different impression. For example, a rate per transfer may look higher than a rate per cycle that includes patients who did not reach transfer. Ask the clinic to specify the exact denominator and whether it includes all patients or only a selected subgroup.

Check the age bands

Success rates vary significantly with age. A clinic may advertise an overall rate that is not relevant to your age group. Ask for the success rate broken down by age bands, such as under 35, 35-37, 38-40, and over 40. If the clinic does not provide age-specific data, ask why. This information helps you set realistic expectations for your own situation.

Define the outcome

What does the clinic mean by “success”? Common definitions include a positive pregnancy test, a clinical pregnancy (confirmed by ultrasound), a live birth, or a healthy baby. Live birth is the most meaningful outcome for most patients, but it is not always the one advertised. Ask the clinic to specify the outcome definition and whether it is based on a single embryo transfer or multiple transfers.

Consider the timing of the data

Success rates can change over time due to improvements in technology, changes in patient population, or other factors. Ask the clinic for the time period of the data. Is it from the last year, the last three years, or a longer period? Also ask whether the data is audited or verified by an external body. This helps you assess the reliability of the figure.

Compare like with like

When comparing IVF success rates in Thailand or elsewhere, make sure you are comparing similar groups. For example, compare rates for the same age band, the same type of embryo transfer (fresh or frozen), and the same outcome definition. Also consider whether the clinic treats a similar patient profile to yours. A clinic that specializes in certain conditions may have different outcomes than a general clinic.

Questions to ask the clinic

• What is your success rate for my age group?
• What is the denominator for that rate?
• What is the outcome definition?
• Is the rate based on fresh or frozen transfers?
• How many cycles were included in the calculation?
• What is the time period of the data?
• Is the data audited or verified?
• Do you have separate rates for patients with similar diagnoses to mine?

Next steps: your checklist

1. Write down the advertised rate and the exact wording used.
2. Ask the clinic for the denominator, age bands, and outcome definition.
3. Request the data in writing, if possible.
4. Compare the rate with national or regional averages, but remember that averages may not apply to you.
5. Discuss your personal medical history with the clinic to understand how it may affect your chances.
6. Use the answers to make an informed decision about your treatment plan.

Remember, a success rate is a statistical summary, not a prediction for your individual case. Many factors influence your personal chances, including your age, the cause of infertility, and the clinic’s approach. Use the questions above to get the information you need, and always consult with your doctor about your specific situation.

Frequently asked questions

Why is the denominator important when looking at IVF success rates?

The denominator tells you which patients are included in the calculation. A rate per embryo transfer may look higher than a rate per cycle that includes patients who did not reach transfer. Knowing the denominator helps you understand what the number actually represents.

What is the most meaningful IVF success rate outcome?

For most patients, the live birth rate is the most meaningful outcome. However, clinics may advertise positive pregnancy tests or clinical pregnancies. Always ask for the outcome definition to ensure you are comparing like with like.

How do age bands affect IVF success rates?

Success rates typically decline with age. An overall rate may not reflect your age group. Ask for age-specific rates to get a more accurate picture for your situation.

Should I compare IVF success rates across different clinics?

Yes, but only if you compare similar groups: same age band, same outcome definition, and same type of transfer. Also consider the clinic's patient profile and whether it matches yours.

Continue your research

• How to interpret IVF success rates
• Patient resources
• Prepare a private case review

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.