At a glance
A plain-English guide to what happens to embryos in the IVF laboratory in Thailand, from egg retrieval to biopsy and PGT testing, with practical questions to ask your clinic.
If you are considering IVF with preimplantation genetic testing (PGT) in Thailand, you may wonder what actually happens to your embryos in the laboratory. In short, the pathway usually moves from egg retrieval and fertilisation, through several days of embryo culture, to a small biopsy of cells from each embryo, followed by genetic testing and a report that your clinic uses to decide which embryos may be suitable for transfer. The exact steps, timelines and laboratory arrangements vary by clinic, so treat this as a map of the journey and a list of questions to confirm directly with your treating team.
At a glance
- The laboratory pathway is a sequence: retrieval, fertilisation, culture, biopsy, testing, reporting and possible transfer.
- PGT is a group of tests, not a single test. PGT-A, PGT-M and PGT-SR look at different things.
- PGT cannot guarantee a pregnancy, a live birth or a healthy child, and it is not necessary or suitable for everyone.
- Your clinic should explain who performs each step, how embryos are tracked, and what happens to embryos that are not transferred.
- Ask for written information about costs, consent, storage and reporting before you start.
Step 1: Egg retrieval and fertilisation
The laboratory pathway begins before the embryology laboratory itself. After ovarian stimulation and egg retrieval, the eggs are collected and prepared for fertilisation. Fertilisation may be attempted by mixing eggs and sperm together, or by injecting a single sperm into an egg (ICSI). The choice depends on the clinical situation and is a decision your treating clinician should discuss with you.
Once fertilisation occurs, the resulting structure is called a zygote. It then begins to divide and develop into an embryo. The laboratory monitors this early development, but the details of how often and how closely embryos are checked can differ between clinics.
Step 2: Embryo culture
Embryos are kept in a controlled environment designed to support development. This is often called embryo culture. Culture conditions, the type of incubator, and whether the laboratory uses time-lapse imaging or standard daily checks are laboratory-specific. No single approach is universally required, and clinics may use different systems.
Embryos are usually observed over several days. Some may stop developing, and some may develop more slowly than others. The embryology team records these observations. If you are curious about how your embryos are progressing, ask what information the clinic can share and when.
Step 3: Embryo biopsy
For PGT, a small number of cells are typically removed from each embryo. This is called a biopsy. The timing can vary: some clinics biopsy embryos at the blastocyst stage, usually around day five or six of development, while others may use a different stage. The biopsy is intended to obtain DNA for testing without removing cells that the embryo needs to continue developing.
Biopsy is a laboratory procedure, and the embryologist performing it should be experienced. Ask who performs the biopsy, how many cells are taken, and what the clinic’s approach is if an embryo is not suitable for biopsy.
Step 4: What PGT tests look at
PGT is an umbrella term. The three main categories you may hear about are:
- PGT-A (aneuploidy screening): looks at the number of chromosomes in the biopsied cells. It can identify embryos with an abnormal number of chromosomes, but it does not test for all genetic conditions and does not guarantee a healthy pregnancy.
- PGT-M (monogenic disease): looks for a specific inherited condition caused by a single gene, when a known familial variant has been identified. It is usually planned in advance with a genetics team.
- PGT-SR (structural rearrangement): looks at chromosomes when a parent has a known structural rearrangement, such as a translocation.
Each test has limitations. A result is a laboratory finding, not a diagnosis of your future child. Some results may be unclear, and some embryos may not provide enough DNA for a result. Your clinic should explain what a result can and cannot tell you.
Step 5: Laboratory workflow and embryo tracking
In a busy laboratory, multiple embryos from multiple patients may be handled on the same day. Reliable tracking is therefore essential. Clinics use labelling, witnessing procedures and documentation to help ensure that each embryo is correctly identified throughout culture, biopsy, testing and storage.
You may want to ask how embryos are labelled, how identity checks are performed, and how the laboratory links the biopsy sample to the correct embryo. You can also ask how results are reported back to your clinician and to you.
Step 6: Results, reporting and next steps
After testing, the laboratory issues a report. Your clinician then discusses which embryos may be suitable for transfer, taking into account the test result, embryo development and your overall clinical picture. Some embryos may be recommended for transfer, some may be kept in storage, and some may not be suitable. The decision is not based on the PGT result alone.
If no embryo is available for transfer after testing, your clinic should explain the possible reasons and discuss alternatives. PGT is one option among several, and it is not a required step for all patients.
Questions to ask your clinic about the laboratory pathway
- Who performs the biopsy, and what is their experience?
- At what stage are embryos biopsied, and why?
- How are embryos tracked and identified in the laboratory?
- What PGT test is being proposed, and what can it detect or miss?
- What happens if a result is unclear or no result is obtained?
- How and when will I receive the laboratory report?
- What are the costs of culture, biopsy, testing and storage, and what is included?
- What are the clinic’s policies on embryo storage, consent and disposal?
- What alternatives are available if I choose not to do PGT?
Practical next steps
- Ask your clinic for a written summary of the laboratory pathway, including who does what.
- Request an explanation of the specific PGT test being recommended and its limitations.
- Confirm all costs in writing, including any separate laboratory or genetics fees.
- Ask how embryos will be stored and what happens if you move or stop treatment.
- Keep a copy of your consent forms and laboratory reports.
Where to learn more
You can compare clinics and their laboratory services on our hospitals page. For a broader overview of PGT in Thailand, see our PGT in Thailand guide. Our guides section covers related planning topics, and the FAQ answers common questions about testing and treatment.
Frequently asked questions
Is PGT required for all IVF patients in Thailand?
No. PGT is an optional laboratory test that may be recommended for some patients based on their history or genetic risk. It is not required for everyone, and your clinic should explain why it is or is not being suggested in your case.
Does PGT guarantee a healthy baby?
No. PGT can provide information about certain chromosomal or genetic findings, but it cannot guarantee a pregnancy, a live birth or a healthy child. It also does not detect every possible condition. Your clinic should explain the limits of the specific test being used.
How long does the laboratory pathway take?
Timelines vary by clinic and by the test being performed. Embryo culture usually lasts several days, and testing may add additional time. Ask your clinic for an estimated schedule for your own cycle.
What happens to embryos that are not transferred?
Embryos that are not transferred may be stored, donated, used for research or disposed of, depending on your consent and the clinic's policies. Ask for written information about storage duration, costs and your options.
Can I ask to speak to the embryologist?
Many clinics allow patients to ask questions through their treating clinician. Whether you can speak directly to an embryologist depends on the clinic. It is reasonable to ask how laboratory questions are handled.
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.
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