EMBRYO TESTING WITH DEFINED LIMITS
Preimplantation genetic testing: PGT uses and limits
PGT evaluates cells sampled from an embryo created through IVF. Depending on the indication, it may assess chromosome number or a known inherited condition, but it does not test every disease or guarantee implantation or a healthy birth.
Indication first
The exact type of PGT is chosen for a defined clinical question.
Laboratory coordination
Biopsy, freezing, result categories and timing are explained.
Residual risk
Inconclusive, mosaic and untested conditions remain possible.
DIFFERENT TESTS, DIFFERENT QUESTIONS
What PGT may be designed to evaluate
PGT-A, PGT-M and PGT-SR address different questions. Genetic counseling helps clarify whether testing is appropriate and how results could change decisions.
Chromosome screening
PGT-A estimates chromosome copy number in the sampled cells; it is not a complete health test.
Known inherited conditions
PGT-M requires case-specific preparation for a defined familial condition. Because a residual risk of error remains, prenatal diagnostic testing to confirm the result should be offered if pregnancy occurs, with counseling about benefits, risks and alternatives. The decision is individual and informed.
ASRM: PGT-M guidance (2023)Structural rearrangements
PGT-SR may be considered when a genetic contributor has a confirmed chromosome rearrangement.
FROM COUNSELING TO RESULT
How testing fits into an IVF cycle
Define the indication
Review history, diagnosis, genetics and alternatives.
Create and culture embryos
Complete IVF and reach the stage appropriate for biopsy.
Biopsy and freeze
Sample cells and cryopreserve embryos while testing is performed.
Interpret and plan
Review result categories, residual risk and transfer options.
DECISION SUPPORT
A result is not a guarantee
Biopsy samples only some cells, laboratories use defined thresholds and embryo development remains biologically variable. Prenatal screening or diagnosis may still be recommended after pregnancy.
- Confirm the exact PGT type and clinical question.
- Discuss the possibility of no result or no embryo suitable for transfer.
- Review prenatal testing recommendations before treatment.
Important limitation: PGT cannot detect every genetic or developmental condition and cannot guarantee implantation, pregnancy or live birth.
Ask whether PGT answers your clinical question
Share genetic reports, family history and prior IVF results for an individual review before committing to testing.
CLINICAL INFORMATION
Preimplantation genetic testing (PGT): the short answer
What it is
Testing of cells sampled from embryos created through IVF to address a specific chromosomal or genetic question before transfer selection.
What shapes the recommendation
The indication depends on the genetic question, history, age, available embryos and the limitations of testing.
Important limit
The result does not test for every condition or guarantee implantation or live birth; prenatal assessment may still be indicated.
CLEAR CLINICAL INFORMATION
Frequently asked questions about preimplantation genetic testing
Concise answers to help you prepare for a consultation and understand what requires an individual medical assessment.
What is PGT?
Preimplantation genetic testing evaluates cells sampled from embryos created through IVF. Different PGT types answer different genetic questions, so the indication and limitations must be explained.
Does every IVF cycle need PGT?
No. PGT is not automatically beneficial for every patient. Age, reproductive history, family history, the specific genetic question and the number of embryos all affect the decision.
Can PGT identify every genetic or health condition?
No. PGT has technical and biological limits and does not test for every condition. Prenatal screening or diagnostic testing may still be discussed after pregnancy begins.
Does a reported euploid embryo guarantee a live birth?
No. A result can inform embryo selection, but implantation, miscarriage and pregnancy outcomes also depend on embryo, uterine and general health factors.
CLINICAL DECISION GUIDE
What PGT can and cannot answer
Preimplantation genetic testing is performed on cells sampled from an embryo created through IVF. Depending on the indication, it may evaluate chromosome number or a specific inherited condition, but it does not test every disease and does not guarantee implantation, pregnancy or a healthy birth.
The decision should consider age, family history, the condition being investigated, the number of embryos available, laboratory limitations, possible inconclusive results and whether confirmatory prenatal testing will be recommended. Genetic counseling is particularly important when testing for a known familial condition.
- Define the exact type of PGT and the clinical question.
- Discuss biopsy, freezing, result categories and the possibility of no transferable embryo.
- Review alternatives, residual risk and prenatal diagnostic options.