When Is Preimplantation Genetic Testing (PGT) Necessary in IVF?

Advances in reproductive medicine have transformed in-vitro fertilization (IVF) from a one-size-fits-all procedure into a highly individualized process. One of the most significant developments in this evolution is Preimplantation Genetic Testing (PGT). While widely discussed, PGT is often misunderstood particularly around when it is truly necessary and when it may not add meaningful value.

This article serves one clear informational intent: to explain when Preimplantation Genetic Testing (PGT) is medically indicated in IVF, how clinicians decide its use, and what patients should realistically expect from it.

What Is Preimplantation Genetic Testing (PGT)?

Preimplantation Genetic Testing is a laboratory technique used during IVF to analyze embryos for specific genetic or chromosomal abnormalities before implantation.

The goal of PGT is not to “improve” embryos, but to identify embryos with a higher likelihood of normal development, thereby reducing certain risks associated with implantation failure, miscarriage, or inherited genetic disease.

PGT is performed only after:

• IVF has created embryos
• Embryos have developed to the blastocyst stage
• A small number of cells are biopsied from each embryo

Types of Preimplantation Genetic Testing

PGT is an umbrella term that includes three main categories:

Understanding these distinctions is critical, because the indication for PGT depends on the specific clinical scenario.

Why PGT Is Not Recommended for Everyone

A common misconception is that PGT is a routine or mandatory step in IVF. In reality:

• Many IVF cycles result in healthy pregnancies without PGT
• PGT does not guarantee pregnancy or a healthy baby
• PGT adds cost, time, and laboratory complexity

For this reason, responsible fertility practice emphasizes selective and evidence-based use of PGT rather than universal application.

When Is Preimplantation Genetic Testing (PGT) Necessary?

PGT is typically considered when there is a clearly defined medical indication. Below are the most common scenarios where clinicians may recommend it.

1. Advanced Maternal Age

Maternal age is one of the strongest predictors of chromosomal abnormalities in embryos.

Key facts:

• The rate of aneuploidy increases significantly after age 35
• By the early 40s, a majority of embryos may be chromosomally abnormal

In such cases, PGT-A may help identify embryos with normal chromosome numbers, potentially reducing the risk of miscarriage and repeated failed transfers.

However, it is important to note that:

• PGT-A does not create healthy embryos
• It only helps in selection among available embryos

2. Recurrent Pregnancy Loss

Recurrent miscarriage commonly defined as two or more consecutive pregnancy losses can be emotionally and physically exhausting.

In some couples, losses are due to:

• Chromosomal abnormalities in embryos
• Balanced translocations in one partner

PGT may be recommended to:

• Identify chromosomally normal embryos
• Reduce the likelihood of further miscarriage

In these cases, PGT is used as a diagnostic and preventive tool, not a treatment in itself.

3. Repeated IVF Failure

When multiple IVF cycles have resulted in:

• Failed implantation
• Poor embryo development
• Early pregnancy loss

Clinicians may consider PGT to assess whether embryonic chromosomal factors are contributing to poor outcomes.

PGT can provide:

• Insight into embryo quality
• Guidance for future treatment planning

It does not, however, address uterine or hormonal causes of failure.

4. Known Genetic Disorders in the Family

PGT-M is specifically designed for couples with:

• Known inherited genetic conditions
• High risk of passing on a serious disease

Examples include:

• Thalassemia
• Cystic fibrosis
• Certain muscular dystrophies
• Single-gene metabolic disorders

In these cases, PGT allows embryos without the specific mutation to be selected for transfer.

This is one of the clearest and strongest indications for Preimplantation Genetic Testing.

5. Structural Chromosomal Abnormalities in Parents

Some individuals carry balanced chromosomal rearrangements, such as:

• Translocations
• Inversions

While carriers are often healthy themselves, these rearrangements can lead to:

• Infertility
• Recurrent miscarriage
• Chromosomally unbalanced embryos

PGT-SR is used in these cases to identify embryos with a balanced or normal chromosomal structure.

6. Severe Male Factor Infertility

In certain cases of severe male infertility, particularly when:

• Sperm count is extremely low
• There is a history of genetic abnormalities

Clinicians may consider PGT as part of a broader evaluation, although male factor alone is not an automatic indication.

Situations Where PGT May Not Be Necessary

PGT is generally not recommended when:

• The woman is young with good ovarian reserve
• There is no history of miscarriage or genetic disease
• Embryo quality is consistently good
• IVF is being attempted for the first time

In such scenarios, standard IVF outcomes are often comparable without genetic testing.

How Doctors Decide: The Clinical Decision Process

The decision to use Preimplantation Genetic Testing is based on:

• Medical history
• Age and reproductive profile
• Prior IVF outcomes
• Genetic counseling

Responsible IVF centers including specialized settings such as Slavica IVF and Research  Center emphasize case-by-case assessment rather than routine testing.

PGT should always be preceded by:

• Detailed counseling
• Discussion of benefits and limitations
• Informed consent

Benefits of PGT (When Appropriately Used)

When used for the right indications, PGT may:

• Reduce miscarriage risk
• Shorten time to pregnancy
• Avoid transmission of serious genetic diseases
• Provide clarity after repeated IVF failures

These benefits are context-dependent, not universal.

Limitations and Considerations

PGT has important limitations that must be understood:

• It does not guarantee implantation
• Mosaicism can complicate results
• Not all embryos survive biopsy and freezing
• False positives and negatives are possible

This is why professional guidelines caution against overuse.

PGT in Nepal: Current Context

The availability of PGT in Nepal has expanded in recent years, allowing couples access to advanced reproductive diagnostics closer to home.

Key considerations in the local context include:

• Appropriate patient selection
• Laboratory expertise
• Genetic counseling support

Choosing a qualified PGT clinic with transparent protocols and ethical standards is essential for meaningful outcomes.

Ethical and Emotional Dimensions

PGT raises important ethical questions, including:

• Decision-making around embryo selection
• Emotional impact of genetic findings
• Cultural and personal beliefs

These aspects are integral to patient-centered fertility care and should be addressed openly.

Frequently Asked Questions (FAQ)

Is Preimplantation Genetic Testing mandatory in IVF?

No. PGT is optional and recommended only for specific medical indications.

Does PGT improve IVF success rates?

In selected cases, it may reduce miscarriage and time to pregnancy, but it does not guarantee success.

Is PGT safe for embryos?

When performed by experienced laboratories, embryo biopsy is generally considered safe, though no procedure is entirely risk-free.

Can PGT detect all genetic diseases?

No. PGT targets specific abnormalities and cannot screen for all possible conditions.

Is PGT useful for first-time IVF patients?

Usually not, unless there is a known genetic risk or other strong indication.

Medical Review Note

This article is based on established reproductive medicine research, international IVF guidelines, and current clinical understanding as of 2026.
It is intended for educational purposes only and does not replace personalized medical advice, diagnosis, or genetic counseling.

Key Takeaway

Preimplantation Genetic Testing is a powerful diagnostic tool but only when used for the right reasons.

Understanding when PGT is necessary in IVF helps couples make informed, ethical, and medically sound decisions, avoiding unnecessary intervention while maximizing the potential for healthy outcomes.

More Related Blogs:

• Genetic Diseases That Cause Infertility: How PGT Helps in Early Detection

• Sperm DNA Fragmentation: What It Means for Male Fertility and IVF Outcomes