At a glance
Understand PGT-A, PGT-M, and PGT-SR results including euploid, aneuploid, mosaic, and inconclusive findings, and what each means for embryo transfer decisions.
Understanding PGT Results
Preimplantation Genetic Testing (PGT) is a technique used during IVF to screen embryos for genetic abnormalities before transfer. Results from a Thailand lab typically fall into categories such as euploid, aneuploid, mosaic, or inconclusive. This guide explains these terms and what they mean for your next steps.
Types of PGT
PGT-A (Aneuploidy Screening)
PGT-A checks embryos for the correct number of chromosomes. A normal result is called euploid, meaning the embryo has the expected 46 chromosomes. An abnormal result is aneuploid, indicating missing or extra chromosomes. Some embryos show a mix of normal and abnormal cells, known as mosaic. Occasionally, the lab cannot give a clear result, labeled inconclusive.
PGT-M (Monogenic Disorders)
PGT-M screens for specific single-gene disorders such as cystic fibrosis or thalassemia. Results indicate whether the embryo carries the disease-causing mutation, is unaffected, or is a carrier (if relevant).
PGT-SR (Structural Rearrangements)
PGT-SR detects chromosomal structural changes like translocations or inversions. Results show whether the embryo has a balanced or unbalanced rearrangement.
Interpreting Your Results
Euploid
A euploid embryo has the correct number of chromosomes and is considered chromosomally normal. For PGT-A, this is generally the preferred category for transfer, as it has the highest chance of implantation and a healthy pregnancy. However, euploid does not guarantee a successful pregnancy or a healthy baby.
Aneuploid
An aneuploid embryo has an abnormal chromosome count, such as trisomy (extra chromosome) or monosomy (missing chromosome). Most aneuploid embryos will not implant or will miscarry. Some may result in a child with a condition like Down syndrome. Transfer of aneuploid embryos is generally not recommended, but you should discuss all options with your doctor.
Mosaic
A mosaic embryo contains both normal and abnormal cells. The proportion of abnormal cells is reported as a percentage (e.g., 20% mosaic). Mosaic embryos may have reduced implantation potential and a small risk of a chromosomal condition. Some clinics consider transfer of low-level mosaics (<20-30%) after counseling. The decision is complex and should involve a genetic counselor.
Inconclusive
An inconclusive result means the lab could not determine the embryo’s chromosomal status due to technical issues, such as failed amplification or poor DNA quality. Your doctor may recommend retesting or consider the embryo for transfer after discussing risks.
What Each Result Means for Transfer Decisions
- Euploid: Highest priority for transfer. Discuss with your doctor.
- Aneuploid: Typically not transferred. Confirm with your clinic’s policy.
- Mosaic: May be considered for transfer if no euploid embryos are available. Requires genetic counseling.
- Inconclusive: Options include retesting or transfer after counseling. Not all labs offer retesting.
Limitations of PGT
PGT is a screening tool, not a diagnostic test. It cannot detect all genetic conditions, and a normal result does not guarantee a healthy baby. Embryo biopsy carries a small risk of damage. PGT is not recommended for everyone; your doctor can help determine if it is appropriate for your situation.
Alternatives to PGT
If PGT is not suitable or you prefer not to test, alternatives include prenatal testing (chorionic villus sampling or amniocentesis) during pregnancy, or using donor eggs or sperm. Discuss these options with your fertility specialist.
Questions to Ask Your Clinic
- What type of PGT was performed (PGT-A, PGT-M, PGT-SR)?
- How are mosaic embryos classified and what are your transfer criteria?
- What is the lab’s inconclusive rate?
- Do you offer retesting for inconclusive embryos?
- What genetic counseling is available?
Additional Resources
For more information, see our guides on PGT in Thailand and IVF guides, or visit our FAQ page.
Frequently asked questions
What does euploid mean in PGT results?
Euploid means the embryo has the correct number of chromosomes (46) and is considered chromosomally normal. It is the preferred category for transfer.
Can a mosaic embryo be transferred?
Yes, some clinics may transfer mosaic embryos, especially if no euploid embryos are available. The decision involves genetic counseling and depends on the level of mosaicism.
What should I do if my PGT result is inconclusive?
Discuss with your doctor whether retesting is possible or if transfer of the embryo is an option after counseling. Not all labs offer retesting.
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.
Need help turning research into a shortlist?
