Preimplantation Genetic Testing (PGT) is a specialised laboratory procedure that may be used during in vitro fertilisation (IVF) to assess embryos for specific genetic or chromosomal conditions before an embryo is selected for transfer. It can help eligible individuals and couples make more informed decisions about their fertility treatment, particularly when there is a known genetic concern or an increased risk of certain chromosomal abnormalities.
At Birla Fertility & IVF, Noida, Dr. Megha Jindal, Center Head, supports patients in understanding fertility treatment options, including when preimplantation genetic testing may be considered as part of an individualised IVF plan.
The term PGS (Preimplantation Genetic Screening) was historically used for testing chromosome numbers. Today, this is generally referred to as PGT-A (Preimplantation Genetic Testing for Aneuploidy). The broader term PGT includes different tests designed to assess specific genetic or chromosomal conditions.
Preimplantation Genetic Testing is performed on a small sample of cells collected from an embryo created through IVF. The sample is analysed in a specialised laboratory to look for particular genetic or chromosomal findings, depending on the type of test recommended.
PGT does not treat a genetic condition or guarantee a successful pregnancy. Instead, the results may help guide embryo selection and reproductive counselling. The suitability of testing depends on medical history, age, family history, previous pregnancy outcomes and the couple’s fertility treatment goals.
PGT-A evaluates embryos for abnormalities in chromosome number, known as aneuploidy. Chromosomal abnormalities can affect embryo development and may contribute to implantation failure or miscarriage.
PGT-A may be discussed in selected IVF cases. However, it is not necessary or beneficial for every patient, and its ability to improve the chance of having a baby varies according to individual circumstances.
PGT-M is used when one or both genetic parents carry, or are at risk of passing on, a specific inherited genetic condition. Testing is designed around the particular condition or genetic variant being investigated.
Examples may include certain inherited blood disorders and other single-gene conditions. Genetic counselling and appropriate laboratory preparation are important before treatment.
PGT-SR may be considered when a genetic parent has a structural chromosome rearrangement, such as a translocation or inversion, that could affect reproductive outcomes.
The test is designed to assess embryos for relevant chromosome imbalances associated with the identified rearrangement.
Preimplantation Genetic Testing may be discussed with individuals or couples who have:
A known inherited genetic condition or a family history of a specific genetic disorder.
A parental chromosome rearrangement that may affect reproductive outcomes.
A history of recurrent pregnancy loss where a genetic or chromosomal factor is suspected.
Specific clinical circumstances in which embryo chromosome testing may be relevant.
Questions about genetic risks before proceeding with embryo transfer.
Not every patient undergoing IVF requires PGT. A fertility specialist and, when appropriate, a genetic counsellor can help assess whether the potential benefits, limitations and costs are appropriate for the individual situation.
The specialist reviews the couple’s medical and reproductive history, previous IVF outcomes, family history and any relevant genetic test results. The recommended type of PGT, if any, is discussed before treatment.
If IVF is appropriate, medication may be used to stimulate the ovaries to develop multiple follicles. The eggs are then collected through a planned medical procedure.
The collected eggs are fertilised with sperm in the laboratory. The resulting embryos are monitored as they develop.
For many PGT protocols, a small number of cells are collected from the outer layer of a blastocyst-stage embryo. The biopsy method and timing depend on the laboratory protocol and the type of genetic test being performed.
The sample is analysed for the specific chromosome or genetic findings relevant to the test. The time required for results varies by test and laboratory.
The fertility team discusses the report and explains which embryos may be suitable for consideration for transfer. In many cases, embryos are frozen while results are awaited, and a later frozen embryo transfer may be planned.
Embryo transfer decisions should take account of the test result, embryo assessment, clinical history and the limitations of the test.
Depending on the indication and test type, PGT may:
Help identify embryos with particular chromosomal or genetic findings.
Support reproductive planning for families at risk of certain inherited conditions.
Provide additional information when considering embryos for transfer.
Help inform discussions about some genetic risks associated with a pregnancy.
Support more personalised counselling during IVF treatment.
The benefits differ between PGT-A, PGT-M and PGT-SR. Testing does not guarantee implantation, an ongoing pregnancy or the birth of a healthy baby.
PGT has limitations that patients should understand before deciding to proceed.
It is not a guarantee of pregnancy: A result considered suitable for transfer does not ensure implantation or a live birth.
Testing has a defined scope: A test only assesses the genetic or chromosomal findings it is designed to detect.
Results may be complex: Some embryos may have mosaic or inconclusive results, requiring specialist interpretation.
A biopsy samples only a small number of cells: The result may not perfectly represent every cell in the embryo.
Not every IVF patient benefits equally: The value of PGT depends on the reason for testing and the patient’s circumstances.
Further pregnancy screening may still be advised: PGT does not replace recommended prenatal screening or diagnostic testing during pregnancy.
Patients should discuss the possible outcomes, limitations, costs and alternatives with their fertility specialist and genetic counsellor before making a decision.
At Birla Fertility & IVF, Noida, Dr. Megha Jindal, Center Head, helps patients explore fertility treatment options based on their medical history and reproductive goals. If genetic testing is being considered, the consultation can help clarify the reason for testing, the type that may be relevant and the questions to discuss with the clinical and laboratory team.
The decision to use PGT should be individualised. A specialist can explain whether it is appropriate in the context of recurrent pregnancy loss, a known inherited condition, a parental chromosome rearrangement or another specific clinical concern.
PGS was the older term commonly used for screening embryos for chromosome-number abnormalities. The current term for this type of testing is PGT-A. PGT is the broader term that also includes PGT-M for specific inherited genetic conditions and PGT-SR for certain structural chromosome rearrangements.
No. PGT is not required for every IVF cycle. Whether it is appropriate depends on factors such as the medical and family history, the reason for IVF and the specific genetic or chromosomal concern.
PGT may help identify certain genetic or chromosomal findings that are relevant to embryo selection, depending on the test used. However, it cannot prevent all miscarriages, and it does not guarantee a successful pregnancy.
No. PGT-A assesses chromosome-number abnormalities. PGT-M is designed to test for specific inherited single-gene conditions, while PGT-SR is used for certain structural chromosome rearrangements.
No. PGT can provide information about the specific genetic or chromosomal findings assessed, but it cannot rule out every genetic condition, birth defect or pregnancy complication. Recommended prenatal care and screening remain important.
Yes. PGT is performed on embryos created through IVF in a laboratory. It is not a test performed on a natural conception before implantation.
The next steps depend on the specific report, the type of test and the clinical circumstances. The fertility specialist and genetic counsellor can explain the result and discuss possible options, which may include further review, additional testing where appropriate, or reconsideration of embryo transfer plans.
It may be considered in selected circumstances, especially when a specific genetic or chromosomal factor has been identified or is suspected. However, recurrent miscarriage has multiple possible causes, and PGT is not appropriate or beneficial in every case. A detailed evaluation is important before choosing treatment.
No. PGT does not replace prenatal screening or diagnostic tests recommended during pregnancy. Patients should discuss appropriate prenatal care with their obstetrician or genetic counsellor.
A fertility consultation can help review your reproductive history, previous test results, family history and treatment goals. Your specialist can explain the potential role of PGT and whether genetic counselling is recommended.
If you are exploring preimplantation genetic testing as part of IVF, consult the fertility team at Birla Fertility & IVF, Noida, to discuss your medical history and available options. Dr. Megha Jindal, Center Head, can help you understand whether PGT may be relevant to your individual treatment plan.
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