At a glance
The number of embryos biopsied for PGT in Thailand depends on several factors, including the number of eggs retrieved, fertilization rate, embryo development, and clinic policies. There is no fixed number; it varies per cycle.
The number of embryos biopsied for preimplantation genetic testing (PGT) in Thailand varies significantly from one patient to another. There is no standard or guaranteed number because the process depends on multiple biological and clinical factors. This article explains the key factors that influence how many embryos reach the biopsy stage, what patients can typically expect, and important questions to ask your clinic.
Key Factors That Determine the Number of Embryos Biopsied
Number of Eggs Retrieved
The starting point is the number of eggs collected during the egg retrieval procedure. This number depends on the patient’s age, ovarian reserve, and response to ovarian stimulation medications. A higher number of mature eggs generally leads to more embryos available for biopsy, but not all eggs will fertilize or develop normally.
Fertilization Rate
After egg retrieval, the eggs are fertilized with sperm (via IVF or ICSI). The fertilization rate is typically around 70-80% in optimal conditions, but it can be lower depending on egg and sperm quality. Only fertilized eggs (zygotes) will continue to develop into embryos.
Embryo Development to Biopsy Stage
For PGT, embryos are usually biopsied at the blastocyst stage, which occurs around day 5 or 6 after fertilization. Not all fertilized eggs will reach this stage. The rate of blastocyst formation varies, but on average, about 40-50% of fertilized eggs may become blastocysts. Embryos that arrest or stop developing before the blastocyst stage cannot be biopsied.
Embryo Quality and Grading
Embryologists grade embryos based on their morphology (appearance). Only embryos that meet certain quality criteria are considered suitable for biopsy. Poor-quality embryos may not be biopsied because they have a lower chance of leading to a successful pregnancy, and some clinics may have policies on which embryos are eligible for testing.
Clinic Policies and Laboratory Practices
Different clinics in Thailand may have varying policies regarding the minimum number of embryos required for PGT, the stage at which biopsy is performed, and whether they biopsy all available embryos or only those that meet specific criteria. Some clinics may recommend PGT only if there are a certain number of embryos, while others may proceed with fewer. It is essential to discuss your clinic’s specific approach.
Typical Range of Embryos Biopsied
While there is no fixed number, many patients who undergo PGT in Thailand may have between 2 and 8 embryos biopsied per cycle. However, some patients may have fewer (1 or none) if embryo development is poor, while others may have more if they produce a high number of eggs and embryos. The number is highly individual.
What Happens After Biopsy?
After biopsy, the cells are sent to a genetic testing laboratory. The results typically take 1-2 weeks. Not all biopsied embryos will be genetically normal. The proportion of normal embryos depends on the patient’s age and other factors. For example, younger patients tend to have a higher percentage of normal embryos. Your clinic will discuss the results and help you decide which embryos to transfer.
Important Questions to Ask Your Clinic
- What is your clinic’s average number of embryos biopsied per cycle for patients with my age and diagnosis?
- At what stage do you perform the biopsy (day 5, day 6, or both)?
- Do you biopsy all available blastocysts, or only those that meet certain quality criteria?
- What is your lab’s success rate for embryo survival after biopsy?
- How long does it take to receive PGT results?
- What are the costs associated with biopsy and testing per embryo?
Uncertainties and Limitations
It is important to understand that the number of embryos biopsied cannot be predicted with certainty before the cycle begins. Even with a good number of eggs, embryo development can be unpredictable. Additionally, PGT itself has limitations, including the risk of inconclusive results, mosaicism, and the fact that it cannot guarantee a healthy baby. Discuss these aspects with your fertility specialist.
Related Reading
For more information, explore our FAQ section and guides on PGT and IVF in Thailand. If you have further questions, contact us for personalized assistance.
Frequently asked questions
Is there a minimum number of embryos required for PGT in Thailand?
Some clinics may have a minimum number of embryos they recommend for PGT, but this varies. It is best to ask your clinic directly about their policy.
Can all embryos be biopsied for PGT?
Only embryos that reach the blastocyst stage (day 5-6) and have sufficient quality are typically biopsied. Not all fertilized eggs will reach this stage.
Does the number of embryos biopsied affect the success rate of PGT?
Having more embryos to biopsy increases the chance of finding at least one genetically normal embryo, but success also depends on embryo quality and other factors.
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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.
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