PGT-P vs. PGT-M: Understanding your embryo screening options during IVF

Preimplantation genetic testing for monogenic disorders (PGT-M) and polygenic conditions (PGT-P) are invaluable embryo screening approaches. While they seem to answer similar questions regarding embryos’ genetic health, their applications are entirely different.

PGT-M is a targeted diagnostic tool with a high degree of accuracy for single-gene mutations that run in the family. PGT-P provides statistical probabilities of late-onset chronic conditions based on thousands of genetic markers. The choice of tests depends on which one is relevant to your genetic profile, and they can also be used simultaneously.

This guide compares PGT-P vs. PGT-M in terms of how they work, what they can reveal about your embryos, their benefits and limitations, and who they are recommended for.

What is PGT-M?

PGT-M is used to detect whether an embryo has inherited a specific genetic variation that causes a known single-gene condition. These conditions are often severe and lifelong.

Some single-gene disorders are recessive, so both parents must carry the same gene mutation for their child to be at risk. In this case, each pregnancy carries a 25% chance of the baby being affected by the condition.

Other conditions are dominant, so only one copy of the mutation is enough to cause the condition, even if the other gene copy is normal. In these cases, a child has a 50% chance of inheriting the disorder if one parent is affected.

X-linked conditions, passed down through the mother’s X chromosome, affect boys more severely. In this case, sex selection through IVF may be recommended.

The goal of PGT-M is to help families avoid passing on a serious inherited disorder to their child.

Source: Anna Shvets

How PGT-M works

PGT-M is a personalized test. Both parents must undergo carrier screening to identify the mutation that puts their child at risk. Once the mutation is confirmed, the laboratory develops a custom DNA probe designed specifically for that family’s gene variations. This probe allows embryologists to scan the embryo's DNA for that exact mutation.

Once embryos are created through IVF, a few cells containing the embryo’s DNA are removed from each one at the blastocyst stage (day 5 or 6 of development), when there are two distinct groups of cells:

1. Inner cell mass, which will develop into a fetus

2. Trophectoderm, the outer layer, which will become the placenta

The cells are removed from the outer layer, minimizing the potential harm to fetal development. The DNA is analyzed with the probe, and the lab determines whether each embryo:

1. Has two healthy copies of the gene, meaning it’s unaffected

2. Carries one copy of the mutation, which means it’s a carrier but not affected

3. Has inherited the disease-causing mutation, in which case it’s not viable

When to use PGT-M

PGT-M is not a general screening test. It’s designed for families with a known specific genetic risk.

It’s commonly recommended for parents who:

• Are carriers of the same recessive conditions

• Are carriers of a dominant condition

• Have a family history of chromosomal abnormalities

• Already have a child with a genetic disorder

  
  

What is PGT-P?

PGT-P examines how multiple genes influence risk for common, adult-onset conditions. These conditions are called polygenic because many genes contribute to the risk. Together, they can make a significant difference in health outcomes.

Source: Henley design studio

How PGT-P works

PGT-P analyzes hundreds of thousands of DNA variants across the entire genome and compares them to large population datasets that link specific patterns of gene variants with a higher or lower risk of particular diseases.

Here’s how it fits in the IVF timeline:

1. Embryo biopsy: As with other preimplantation genetic testing, once embryos are created through IVF, a few cells are taken from their outer layer at the blastocyst stage, and DNA from the cells is sequenced.

2. Risk estimation: Algorithms evaluate the embryo’s genetic variants against reference datasets, and the result is a risk score for each condition analyzed.

3. Comparison across embryos: Instead of giving definitive answers (affected or unaffected), PGT-P shows which embryos have a lower or higher predicted lifetime risk of a specific condition than others.

When to use PGT-P

PGT-P is for all parents who want to understand and optimize their child’s long-term health prospects, but it’s especially relevant for:

• Parents with multiple euploid embryos after PGT-A and PGT-SR, who want information beyond viability to help them choose the best one for transfer.

• Families with a history of chronic conditions who wish to minimize the risk of their child suffering from the same disease.

• Couples already planning preimplantation screening, such as PGT-A or PGT-M, who want deeper insights.

Polygenic embryo screening works best when there are multiple embryos to compare for relative genetic differences. When only a few embryos are available, the test may provide limited additional insight for embryo selection.

Bonus read: Find out how PGT-P compares to PGT-A in our detailed guide.

PGT-P vs. PGT-M comparison across 4 key dimensions

To better understand polygenic vs. monogenic testing and see whether PGT-M or PGT-P (or both) is for you, it helps to look at them side by side across four key dimensions:

1. Scope

2. Accuracy

3. Impact on embryo selection

4. Cost and availability

Source: Tatiana Syrikova

1. Scope of PGT-M vs. PGT-P 

PGT-M is narrow and targeted. It focuses on one gene of concern that is already identified in the parents’ DNA. It is highly effective for families with a specific genetic disorder, but it can’t provide information about other risks outside of that single gene.

PGT-P is broad and predictive. Unlike PGT-M, which only focuses on a single mutation in a single gene, PGT-P looks at how thousands of genetic markers across the entire genome combine to influence risk for common, adult-onset, and chronic conditions.

The table below lists examples of conditions that PGT-P and PGT-M can help identify or assess:

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2. PGT-P vs. PGT-M accuracy

PGT-M is a diagnostic tool. Using customized probes that match the parents’ gene mutation, PGT-M can detect whether an embryo is affected with high precision. Reported accuracy rates are typically above 97%, with some sources reporting 99% accuracy.

Still, results can sometimes be harder to interpret because of mosaicism, when not all cells in the embryo have the same genetic makeup. For example, some cells may be normal while others aren’t.

In contrast, PGT-P is not a diagnostic test but a statistical prediction tool. It examines thousands of genetic variants, each with a small effect on disease risk, and combines them into risk estimates for various conditions.

Additionally, environmental and lifestyle factors, like diet, exercise, or smoking, also play a role, so polygenic risk is never absolute. Instead of producing a “yes or no” result, PGT-P estimates an embryo’s relative risk, i.e., how likely it is to develop a particular condition, compared to the general population.

PGT-P can identify relative differences between embryos, but it can't guarantee whether a condition will or won't develop. Plus, predictive accuracy varies depending on the condition, the size and diversity of the dataset used to estimate the risk.

Source: Daniel Reche

3. Impact on embryo selection

The impact of PGT-M and PGT-P on embryo selection is one of the most practical differences for families going through IVF.

For PGT-M, the decision is straightforward. Embryos that carry disease-causing mutations are excluded from transfer, while embryos without the mutation are prioritized. In cases of recessive disorders, an embryo that is a carrier (has only one copy of the mutation but is not affected) may still be considered for transfer, depending on the number of available embryos, the family’s preferences, and medical guidance.

Because PGT-M addresses a single known condition, the test provides a clear “yes or no” outcome, making embryo selection highly actionable and reducing uncertainty for families at risk of inherited conditions.

PGT-P results add another layer of information to support informed decisions during embryo selection. When several embryos appear chromosomally normal, PGT-P highlights subtle differences in predicted long-term health, allowing you and your care team to prioritize the embryo with the best potential for lifelong well-being.

4. Cost and availability

PGT-M is widely available in many fertility clinics and is considered a standard during fertility care. The cost of PGT-M depends on the disorders being tested and the number of mutations that require analysis. The average cost per cycle ranges from $7,000 to $12,000, which typically includes:

• Embryo biopsy

• Laboratory processing

• Analysis of the specific gene mutations

PGT-P is offered as an add-on to existing embryo testing, such as PGT-M, PGT-A, or PGT-SR. The price is around $2,500 per embryo, excluding the cost of IVF.

Availability of PGT-P is growing, but it’s not yet as widespread as standard genetic testing like PGT-M. If you’re interested to learn more about your embryos and want to give your future child the best possible start in life, you will need to ask your fertility clinic whether they include this option in your fertility treatment.

Know that understanding the PGT results and making informed choices based on them requires expert guidance. A session with a genetic counselor can add to the total cost.

IVF is already demanding, both physically and emotionally, and navigating genetic testing on top of everything can feel overwhelming. It helps to have professional support to guide you through every step.

With Nucleus IVF+, you get access to advanced embryo testing, expert guidance, and personalized support, all integrated into one comprehensive IVF package. From selecting the right clinic to interpreting embryo data and planning each step of the journey, Nucleus provides clarity and confidence, helping you focus on your primary role: growing your family.

Nucleus IVF+: Comprehensive IVF package built for genetic optimization

Nucleus IVF+ is an all-inclusive IVF package that combines advanced genetic testing with personalized guidance so you can make confident, informed decisions throughout your fertility journey:

With more than 120,000 embryos tested through lab partners, over 2,000 IVF cycles completed with partner clinics, and a 95% patient recommendation rate, Nucleus results speak for themselves.

Families who choose Nucleus IVF+ can see up to a 20% higher chance of a successful pregnancy. 

When you’re ready to take the next step, book an onboarding call. From the first conversation, the Nucleus team will be by your side, guiding every detail so you can focus on becoming a parent.

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Featured image source: Creation Hill