PGT Biopsy Procedure in Thailand: What International Patients Should Know About Embryo Biopsy, Lab Steps and Timing

PGT biopsy in Thailand is usually performed on day 5 or day 6 after fertilisation, when an embryo has reached the blastocyst stage. A small sample of trophectoderm cells is removed from the outer layer that will form the placenta, while the inner cell mass is left undisturbed. The sample is then prepared for genetic testing, and the embryo is typically frozen while results are awaited. The exact protocol, timing and laboratory workflow vary by clinic, so confirm the details with your treating hospital.

At a glance

• When: Usually day 5 or day 6 after fertilisation, at the blastocyst stage.
• What is sampled: Trophectoderm cells from the outer layer of the embryo.
• What is not sampled: The inner cell mass, which is the part that develops into the fetus.
• After biopsy: Embryos are commonly frozen while genetic testing is completed.
• Who decides: The treating clinic and embryology team, based on your individual case.

What PGT biopsy means in the IVF process

Preimplantation genetic testing (PGT) is a laboratory step that can be added to an IVF cycle. It involves taking a tiny sample of cells from an embryo and testing that sample for certain chromosomal or genetic features. The biopsy itself is the sampling step; the genetic testing happens afterwards in the laboratory.

PGT is not a treatment for infertility and it does not change the embryo. It is a way of gathering information that your clinic may use when deciding which embryo(s) to consider for transfer. Whether PGT is appropriate for you is a medical decision that depends on your history, your reasons for testing and your clinic’s assessment. This guide explains the general process so you can prepare questions, not so you can decide on your own whether to test.

Why biopsy is usually done at the blastocyst stage

In many clinics, embryo biopsy for PGT is performed on day 5 or day 6 after egg collection, when the embryo has developed into a blastocyst. At this stage the embryo has two distinct parts:

• The inner cell mass, which is the group of cells that goes on to form the fetus.
• The trophectoderm, the outer layer of cells that goes on to form the placenta and other supporting tissues.

Because the trophectoderm and inner cell mass are separate at this stage, a laboratory can remove a few trophectoderm cells while leaving the inner cell mass intact. This is why the procedure is often called a trophectoderm biopsy. It is one reason many clinics prefer blastocyst-stage biopsy over earlier-stage biopsy, though practice patterns differ and your clinic will explain what it recommends for your case.

Step-by-step: what happens during the PGT biopsy procedure

The following is a general sequence. Your clinic may adjust the order or details based on its laboratory protocol.

1. Embryo development check. The embryology team reviews embryos each day after fertilisation. On day 5 or day 6, they identify which embryos have reached the blastocyst stage and appear suitable for biopsy.
2. Preparation in the lab. The selected embryo is placed in a specialised dish under a microscope. The laboratory environment is controlled for temperature and other conditions.
3. Microscopic handling. Using fine instruments, the embryologist stabilises the embryo and creates a small opening in the outer layer. A small number of trophectoderm cells are gently drawn away.
4. Sample handling. The biopsied cells are placed into a labelled tube or well. Correct labelling and tracking are critical so that the sample and the embryo remain linked throughout testing.
5. Embryo handling after biopsy. The embryo is returned to culture medium and monitored briefly. In many clinics, biopsied embryos are then frozen (vitrified) while the genetic test is processed.
6. Genetic testing. The sample is prepared and analysed using the laboratory’s PGT method. The time needed for results varies by clinic and by the type of test.
7. Results review. Your clinic reviews the results with you and discusses which embryo(s) may be considered for transfer, and when.

Biopsy is a laboratory procedure performed on the embryo, not on you. It does not require an additional procedure for the patient on the day of biopsy.

Embryo freezing after biopsy

Because genetic testing takes time, many clinics freeze biopsied embryos and plan a later transfer cycle. This is often called a freeze-all or deferred transfer approach. Freezing after biopsy allows the clinic to wait for test results before deciding which embryo to transfer and when.

Not every clinic or every case follows the same path. Some clinics may discuss a fresh transfer in selected situations, while others routinely freeze all biopsied embryos. The right approach for you depends on your medical situation, your clinic’s laboratory workflow and your treatment plan. Ask your clinic to explain its usual practice and why it recommends that path for you.

Timing: how biopsy fits into your IVF and travel timeline

For international patients, it helps to separate the clinical timeline from the travel timeline. The biopsy itself happens in the laboratory, but your travel plans may need to account for monitoring, egg collection, embryo development and a possible later transfer cycle.

Stage	What generally happens	What to confirm with your clinic
Before treatment	Consultation, testing and planning	Which tests are needed, how long results take, and whether any can be done locally
Ovarian stimulation and monitoring	Medication and scans to prepare for egg collection	How many monitoring visits are expected and where they can be done
Egg collection and fertilisation	Eggs are collected and combined with sperm in the laboratory	What day fertilisation is confirmed and how embryos are monitored
Embryo development	Embryos are cultured and observed, usually to day 5 or day 6	How the clinic decides which embryos reach biopsy stage
Biopsy and freezing	Trophectoderm sample is taken; embryos are commonly frozen	Whether freezing is routine, and how embryos and samples are tracked
Genetic testing	Samples are analysed in the laboratory	Expected turnaround time and how results are communicated
Results and transfer planning	Results are reviewed and a transfer cycle is planned	When transfer can be scheduled and what preparation it involves

This table is a planning aid, not a schedule. Actual timelines depend on your response to treatment, laboratory workload and clinic policy. Ask your clinic for a written outline of the expected sequence for your case.

Questions to ask your clinic about PGT biopsy

Bring these questions to your consultation. The answers will help you understand how your clinic handles biopsy and what to expect.

• On which day after fertilisation does your laboratory usually perform biopsy?
• Do you perform trophectoderm biopsy, and how many cells are typically removed?
• What proportion of embryos in your laboratory reach the blastocyst stage and are suitable for biopsy?
• Are biopsied embryos routinely frozen, and if so, when?
• How are embryos and biopsy samples labelled and tracked?
• How long do genetic test results usually take?
• How will results be explained to me, and by whom?
• What are the possible limitations or uncertainties of the test result?
• What costs are involved in biopsy, testing and freezing, and how are they billed?
• What happens to embryos or samples if I decide not to proceed?

What to confirm before you travel

International patients often need to coordinate clinical care with travel. Before booking, confirm the following with your treating clinic:

• Appointment sequence: Which appointments must be in person and which can be done remotely or locally.
• Length of stay: How long you may need to remain in Thailand for the relevant stages of your cycle.
• Documents: Which identity, medical or consent documents the clinic requires, and whether translations or notarisation are needed.
• Consent: What consent is required for biopsy, genetic testing, freezing and storage of embryos.
• Communication: How the clinic will contact you with results and who will discuss them with you.
• Follow-up: What follow-up is needed after you return home, and whether your local doctor can be involved.
• Costs: What is included in quoted fees and what may be charged separately.

Visa rules, legal requirements and document expectations can change and depend on your nationality and circumstances. Confirm these with the clinic and the relevant official authority rather than relying on general information.

Limits and uncertainties of PGT biopsy

PGT biopsy provides information, not certainty. A test result reflects the cells that were sampled, and biology can be complex. Your clinic should explain what a given result can and cannot tell you, including the possibility of results that are inconclusive or that require careful interpretation. No test can guarantee a particular pregnancy outcome or the health of a future child. Understanding these limits is part of informed decision-making.

Next steps

1. Write down your reasons for considering PGT and your questions.
2. Ask your clinic for its written protocol for biopsy, freezing and testing.
3. Confirm the expected timeline and how it fits with your travel plans.
4. Ask how results will be explained and what options follow each type of result.
5. Review costs and consent documents before committing.

For more context, see our guides to PGT in Thailand, IVF in Thailand, the treatment process and information for international patients.

Frequently asked questions

Is PGT biopsy painful for the patient?

No. The biopsy is performed on the embryo in the laboratory, not on your body. It does not require an additional procedure or anaesthetic for you on the day of biopsy. Any discomfort you experience would relate to other parts of the IVF cycle, such as egg collection, not the biopsy itself.

How long does it take to get PGT results after biopsy?

Turnaround time varies by clinic, laboratory and the type of test used. Some clinics provide results within a few weeks, while others may take longer. Ask your treating clinic for its usual timeframe and how it will communicate results to you.

Are embryos always frozen after biopsy?

Many clinics routinely freeze biopsied embryos while genetic testing is completed, but practice varies. Some clinics may discuss a fresh transfer in selected situations. Ask your clinic what it usually recommends and why that approach would apply to your case.

Does biopsy damage the embryo?

Biopsy removes a small number of trophectoderm cells while leaving the inner cell mass, which forms the fetus, undisturbed. Clinics take care to minimise any impact, but as with any laboratory procedure there are limits and uncertainties. Your clinic can explain what is known about outcomes and what remains uncertain.

Can I do PGT biopsy if I am travelling to Thailand for IVF?

Many international patients travel to Thailand for IVF with PGT, but whether it is suitable for you depends on your medical situation and your clinic's assessment. You will need to plan your travel around monitoring, egg collection, embryo development and a possible later transfer cycle. Confirm the timeline, documents and costs directly with your treating clinic.

Continue your research

• PGT in Thailand overview
• IVF in Thailand guide
• Treatment journey

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.