Embryo Biopsy at a Glance
Embryo biopsy is a laboratory procedure performed during an IVF cycle when preimplantation genetic testing (PGT) is planned. It involves removing a small number of cells from an embryo to be sent for genetic analysis. The biopsy itself does not diagnose or guarantee a healthy pregnancy; it provides information that can help you and your clinic decide which embryos to consider for transfer.
This guide explains the timing, the steps, and the questions you may want to ask before undergoing embryo biopsy as part of PGT in Thailand.
When Does Embryo Biopsy Happen?
Embryo biopsy is not a single event; it is scheduled at a specific stage of embryo development. The timing depends on the type of PGT being performed and the laboratory’s protocols.
- Cleavage-stage biopsy: This occurs on day 3 after fertilization, when the embryo has about 6–8 cells. One or two cells are removed.
- Blastocyst-stage biopsy: This is more common today. It occurs on day 5 or day 6, when the embryo has developed into a blastocyst with a fluid-filled cavity and distinct cell types. A few cells are removed from the trophectoderm, which will become the placenta.
Most clinics prefer blastocyst biopsy because it allows more cells to be sampled without disturbing the inner cell mass that becomes the fetus. However, the exact timing may vary based on embryo development and laboratory protocols.
What Are the Steps of Embryo Biopsy?
The biopsy is performed by an embryologist in a specialized laboratory. The steps are generally as follows:
- Embryo preparation: The embryo is held in place under a microscope using a specialized pipette.
- Creating an opening: A laser or chemical solution is used to create a small opening in the outer shell of the embryo (the zona pellucida).
- Cell removal: A thin needle or pipette is used to gently aspirate the required number of cells.
- Cell handling: The removed cells are placed in a sterile tube for genetic testing.
- Embryo culture: The biopsied embryo is returned to the incubator and continues to develop until transfer or freezing.
The procedure is delicate and requires skilled embryologists. The cells removed are from the trophectoderm (future placenta) or, in day-3 biopsy, from the outer layer of the embryo, not the inner cell mass that becomes the fetus.
Types of PGT and What They Test For
Embryo biopsy is used for different types of PGT, each with a specific purpose:
- PGT-A (aneuploidy): Screens for abnormal numbers of chromosomes, which can cause implantation failure or miscarriage.
- PGT-M (monogenic): Tests for specific single-gene disorders, such as cystic fibrosis or sickle cell anemia.
- PGT-SR (structural rearrangement): Detects chromosomal rearrangements, such as translocations, that may affect embryo development.
Not all embryos are suitable for biopsy, and not all patients need PGT. Your clinic will discuss whether PGT is appropriate based on your medical history and family-building goals.
What Happens After Biopsy?
After the biopsy, the cells are sent to a genetics laboratory for analysis. The results typically take several days to a few weeks, depending on the type of testing and the laboratory’s workload. While waiting, the embryos are usually frozen (vitrified) to preserve them.
Once results are available, your clinic will discuss which embryos are considered suitable for transfer. It is important to understand that PGT results are not a guarantee of a successful pregnancy or a healthy baby. Genetic testing has limitations, and not all abnormalities can be detected.
Risks and Limitations
Embryo biopsy is generally considered safe, but it is an invasive procedure. Potential risks include:
- Damage to the embryo during cell removal.
- Reduced embryo viability, though this is rare.
- Inconclusive results, which may require additional testing or re-biopsy.
Additionally, PGT cannot detect all genetic conditions, and the accuracy of the test depends on the laboratory’s methods and the quality of the sample. It is essential to discuss the limitations with your clinic and genetic counselor.
Questions to Ask Your Clinic
Before undergoing embryo biopsy, consider asking your clinic the following questions:
- What type of PGT do you recommend for my situation, and why?
- At what stage will the biopsy be performed?
- How many cells will be removed, and what is your success rate for biopsy?
- How long will it take to receive results?
- What are the risks and limitations of the biopsy and PGT?
- Will the embryos be frozen after biopsy, and what is the survival rate after thawing?
- What is the cost of the biopsy and PGT, and what does it include?
Next Steps
If you are considering PGT in Thailand, here is a simple checklist to guide your planning:
- Research clinics that offer PGT and embryo biopsy.
- Schedule a consultation to discuss your medical history and testing options.
- Ask about the laboratory’s experience and accreditation.
- Clarify the timeline, costs, and what happens with unused embryos.
- Consider genetic counseling to understand the implications of results.
For more information, explore our PGT in Thailand overview, our guides, and our FAQ section.
Frequently asked questions
Is embryo biopsy painful for the embryo?
Embryos do not have a nervous system, so they do not feel pain. The biopsy is a delicate laboratory procedure performed under a microscope, and the embryo is handled gently to minimize stress.
Can embryo biopsy harm the embryo?
There is a small risk of damage, but it is rare. The procedure is performed by trained embryologists using precise techniques. The removal of a few cells from the trophectoderm is generally considered safe, but it is not without risk.
How long does it take to get PGT results?
The time varies depending on the type of PGT and the laboratory. It can take anywhere from a few days to a few weeks. Your clinic will provide a specific timeline based on their protocols.
Do all embryos survive the biopsy and freezing process?
Most embryos survive, but there is a small risk of damage or loss. The survival rate depends on the embryo quality and the laboratory's expertise. Your clinic can provide their specific data.
Is PGT mandatory for all IVF cycles?
No, PGT is not mandatory. It is an optional test that may be recommended based on maternal age, genetic history, or previous pregnancy losses. Your doctor will discuss whether it is appropriate 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.