When patients are going through IVF, every stage can bring questions, hope and uncertainty. By the time embryo testing is discussed, many couples may already have been through months or years of trying, previous treatment, pregnancy loss, or difficult decisions around the next step.
It is natural to want to know whether anything more can be understood about the embryos before transfer. This is where embryo genetic testing may sometimes be discussed.
Many patients may have heard older terms such as PGS or PGD. These terms are still commonly used online, but the newer terminology is PGT, which stands for Preimplantation Genetic Testing.
PGT refers to genetic testing of embryos created during an IVF cycle before embryo transfer. It is not needed for every patient, but in selected cases, it may help the fertility team understand more about the embryo before deciding the next step.
There are different types of PGT:
PGT-A, which checks the number of chromosomes
PGT-M, which checks for a specific single gene mutation
PGT-SR, which checks for structural rearrangements of chromosomes
PGT-A is the most commonly discussed and most commonly relevant form of embryo genetic testing in IVF. PGT-M and PGT-SR are usually done only in selected cases.
At Janini IVF, Delhi, embryo testing is discussed with care, based on the patient’s age, fertility history, embryo development, previous IVF outcomes, miscarriage history, and any known genetic background.
PGT-A, PGT-M and PGT-SR are all types of embryo genetic testing, but they are used for different reasons.
PGT-A checks whether embryos have the expected number of chromosomes. This is the most commonly discussed type of PGT in IVF.
PGT-M checks for a specific single gene mutation. It may be used when there is a known inherited genetic condition in the family.
PGT-SR checks for structural rearrangements of chromosomes. It may be used when one partner has a known chromosomal rearrangement, such as a translocation or inversion.
Not every patient needs all three. In fact, most patients who are discussing embryo testing in IVF are usually discussing PGT-A.
PGT-A stands for Preimplantation Genetic Testing for Aneuploidy.
This test checks whether an embryo has the expected number of chromosomes. A typical human embryo should have 46 chromosomes. If an embryo has missing or extra chromosomes, this is called aneuploidy.
PGT-A does not test for every possible genetic condition. It mainly looks at chromosome number.
This distinction is important because patients may sometimes feel that genetic testing can give complete certainty. PGT-A can provide useful information in selected cases, but it cannot answer every question or remove every risk from IVF treatment.
PGT-A may help provide more information about embryo chromosome number before transfer, but it does not guarantee pregnancy.
PGT-A is the newer term often used instead of PGS.
PGS stood for Preimplantation Genetic Screening. Many patients still search for PGS because the term was used for many years. However, when the test is checking the number of chromosomes in embryos, the updated term is usually PGT-A.
So, if you are searching for “PGS in IVF,” the information you are looking for may now be referred to as PGT-A.
PGT-A may be considered in selected IVF cases where embryo chromosome information may help with treatment planning.
It may be discussed in situations such as:
advanced maternal age
repeated IVF failure
repeated miscarriage
previous pregnancy affected by a chromosomal abnormality
several embryos available and a need to guide embryo selection
a clinical history where embryo chromosome number may be relevant
This does not mean that everyone in these situations will definitely need PGT-A. It means the fertility specialist may discuss whether the test is useful in that particular case.
Every patient’s history is different. For some, PGT-A may be part of the plan. For others, IVF without embryo genetic testing may still be appropriate.
No, every IVF patient does not need PGT-A.
This is important to say clearly, because patients can sometimes feel that they are missing something if they do not do every available test. PGT-A is not a routine requirement for all IVF cycles.
A fertility clinic will usually consider the full picture before advising whether PGT-A may be useful. This may include:
age
ovarian reserve
number of embryos available
embryo development
previous IVF history
miscarriage history
known genetic concerns
overall treatment goals
The aim is not to add more tests automatically. The aim is to decide whether the test will give information that may genuinely help with treatment planning.
PGT-A may help in selected cases by giving more information about embryo chromosome number before transfer.
However, PGT-A does not guarantee pregnancy. It also does not guarantee that an embryo will implant or that a pregnancy will continue.
IVF outcome depends on many factors, including:
embryo quality
chromosome status
uterine health
age
ovarian reserve
sperm factors
hormone environment
overall reproductive health
PGT-A can help guide embryo selection in some cases, but it should be understood as one part of IVF planning, not as a promise of success.
PGT-A may sometimes be discussed after repeated IVF failure, especially if embryo chromosome number may be one possible factor.
Repeated IVF failure can be deeply distressing. Patients may feel confused, exhausted, or unsure whether to continue treatment. In this situation, the fertility specialist may review several factors, including embryo development, uterine factors, sperm health, ovarian response, transfer history and whether embryo testing may be useful.
PGT-A may help identify embryos with the expected number of chromosomes, but it is not the only factor that matters. A careful review of the whole IVF cycle is usually needed before deciding the next step.
PGT-A may be discussed in some cases of repeated miscarriage because chromosome abnormalities can be one possible reason for pregnancy loss.
However, miscarriage can happen for many reasons. These may include embryo chromosome changes, uterine factors, hormone issues, immune-related factors, blood clotting concerns, medical conditions, age-related factors, or sometimes no clearly identifiable cause.
For patients who have experienced miscarriage, this discussion needs to be handled with care. PGT-A may provide useful information in selected cases, but it cannot prevent every miscarriage or explain every loss.
A fertility specialist may recommend a wider evaluation before deciding whether PGT-A is appropriate.
PGT-A can provide useful information, but it also has limitations.
PGT-A:
checks chromosome number, not every genetic condition
does not guarantee pregnancy
does not guarantee implantation
does not prevent all miscarriages
may not be suitable for every embryo
needs careful interpretation
should be considered as part of the full IVF plan
This can be difficult for patients because it may feel like testing should give certainty. In reality, embryo testing can give more information, but it cannot control every factor involved in IVF or pregnancy.
What Is PGT-M?PGT-M stands for Preimplantation Genetic Testing for Monogenic disorders.
This test is used when there is a known risk of a specific single gene condition. It may be discussed if one or both partners carry a known gene mutation that could be passed on to a child.
PGT-M is different from PGT-A. PGT-A checks chromosome number. PGT-M checks for a specific inherited gene condition.
PGT-M is usually done only in selected cases where there is a clear genetic reason. It is not a routine IVF test.
PGT-M may be considered when a couple has a known risk of passing on a single gene disorder.
This may include cases where:
one or both partners carry a known genetic mutation
there is a family history of a single gene disorder
a previous child or pregnancy was affected by a known genetic condition
genetic counselling has identified a specific inherited risk
PGT-M usually requires careful planning. In many cases, genetic counselling and specific laboratory preparation are needed before the IVF cycle.
For patients, this can feel like a lot to take in. The purpose of counselling is to explain the options clearly and help the couple make an informed decision.
PGT-SR stands for Preimplantation Genetic Testing for Structural Rearrangements.
This test is used when there is a known structural rearrangement of chromosomes, such as a translocation or inversion.
A person may carry a balanced chromosomal rearrangement and be healthy themselves. However, embryos may sometimes inherit an unbalanced arrangement, which may increase the risk of failed implantation, miscarriage, or genetic problems in the pregnancy.
PGT-SR is also used only in selected cases. It is not commonly needed for every IVF patient.
PGT-SR may be considered when one partner has a known chromosome structural rearrangement.
This may be identified through genetic testing, karyotyping, previous pregnancy history, or repeated pregnancy loss evaluation.
PGT-SR may be discussed in cases such as:
known balanced translocation in one partner
known inversion or structural rearrangement
repeated miscarriage linked to chromosomal rearrangement
previous pregnancy affected by an unbalanced chromosome result
genetic counselling recommending embryo testing
Like PGT-M, PGT-SR is a specialised test and is usually discussed only when there is a specific reason.
Yes. PGT-A is the most commonly done and most commonly relevant type of PGT in IVF.
PGT-M and PGT-SR are important tests, but they are usually done only in selected cases. PGT-M is used when there is a known single gene mutation. PGT-SR is used when there is a known structural rearrangement of chromosomes.
For most patients asking about embryo screening during IVF, the relevant discussion is usually around PGT-A.
Embryo genetic testing usually involves taking a small number of cells from an embryo, often at the blastocyst stage, and sending them for testing.
This is a specialised laboratory process. The decision to do embryo biopsy and testing should be made after discussing the possible benefits, limitations and risks with the fertility specialist and embryology team.
Not every embryo may be suitable for biopsy. The decision depends on embryo development, embryo quality and the overall clinical plan.
Chromosomes carry genetic information. For an embryo to grow normally, the number of chromosomes matters.
If an embryo has an abnormal number of chromosomes, it may not implant, may stop developing, or may lead to miscarriage. This is one reason PGT-A may be discussed in certain IVF cycles.
For patients who have experienced a failed cycle or pregnancy loss, this conversation can feel emotionally heavy. It is important to understand that chromosome abnormalities are often not caused by anything the patient did or did not do. They can happen naturally during egg or embryo development, and the risk may increase with age.
The decision to do PGT-A should be made after a clear discussion with a fertility specialist.
Patients may want to ask:
Why is PGT-A being suggested in my case?
What will the test tell us?
What will it not tell us?
How many embryos may be available for testing?
What happens if no embryo is suitable for transfer?
Does my history make PGT-A useful?
Are there any limitations I should understand?
There is no one right answer for every patient. The right decision depends on the medical history, emotional readiness, number of embryos, previous treatment experience and what the couple feels comfortable with after counselling.
You may want to ask a fertility clinic about PGT-A if you are undergoing IVF and want to understand whether embryo chromosome testing is relevant to your case.
It may be especially worth discussing if there is:
advanced maternal age
repeated IVF failure
repeated miscarriage
previous chromosomal abnormality in pregnancy
a known genetic concern
multiple embryos and uncertainty around embryo selection
confusion about older terms such as PGS or PGD
At Janini IVF, Delhi, embryo genetic testing is discussed with care and only when clinically relevant.
If you have been advised PGT-A, PGT-M or PGT-SR, or if you are confused by older terms such as PGS or PGD, a consultation can help clarify what the test means and whether it applies to your IVF plan.
PGT-A is the most commonly relevant form of embryo genetic testing because it checks chromosome number. PGT-M and PGT-SR are usually reserved for selected cases involving known genetic mutations or structural chromosome rearrangements.
A structured consultation at Janini IVF can help review your age, IVF history, miscarriage history, embryo development, genetic background and treatment goals before deciding whether embryo genetic testing may be appropriate.
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