PGT-M and Genetic Counselling: When a Family Should Start the Conversation

PGT-M stands for preimplantation genetic testing for monogenic disorders. In plain terms, it is a laboratory test performed on embryos created through IVF to look for a specific single-gene condition that is already known to run in a family. It is not a general screen for every possible genetic problem, and it is not a test that can be arranged quickly at the last minute. PGT-M requires a defined genetic target, a laboratory set-up built around that target, and usually a genetic counselling conversation before ovarian stimulation begins.

If you are researching this because of a known condition, a family history, or a previous affected pregnancy, the useful question is not only “what is PGT-M?” but “when should we start talking to a genetic counsellor?” The short answer: earlier than most people expect, ideally before IVF dates are booked.

What PGT-M actually tests for

PGT-M is designed for a known monogenic condition — a condition linked to a specific gene or a specific inherited change (often called a pathogenic variant or mutation). The HFEA describes PGT-M as testing that concerns a known monogenic condition, and notes that the treating team and a genetic counsellor should discuss the relevant history, test design and suitability. That framing matters: PGT-M is built around a known target, not discovered from scratch during an IVF cycle.

Because the test is tailored, the laboratory needs information about the family’s specific variant before it can design a reliable test. This is one reason the process starts with genetics, not with stimulation medication.

How PGT-M differs from PGT-A and PGT-SR

These three tests are often mentioned together, but they answer different questions. The HFEA distinguishes PGT-M (known monogenic conditions) from PGT-SR (chromosomal structural rearrangements), and notes these tests address different questions. PGT-A is different again: it assesses chromosome number in cells sampled from an embryo, and the HFEA notes it has limitations and can produce incorrect findings.

Test	What it looks at	Typical reason it is raised
PGT-M	A known single-gene condition in the family	A known familial variant, carrier couple, or previously affected child or pregnancy
PGT-SR	Chromosomal structural rearrangements	A known rearrangement in a parent
PGT-A	Chromosome number in sampled embryo cells	General chromosome-number assessment; limitations apply

None of these tests guarantees a successful pregnancy or a healthy child. A result is information that you and your clinicians interpret together, alongside other factors.

When a family might seek genetic counselling

Genetic counselling is a conversation with a trained professional about inheritance, testing options, and what a result could mean for you and your family. Families often start this conversation in situations such as:

• A known condition in the family. A relative has a confirmed single-gene condition, and you want to understand whether it could be passed on.
• You or your partner are known carriers. Carrier status for the same condition in both partners is a common reason PGT-M is discussed.
• A previously affected child or pregnancy. A prior diagnosis in a child or pregnancy often prompts questions about future planning.
• Family history without a confirmed diagnosis. Sometimes the pattern is unclear, and the first step is working out whether a single-gene condition is actually involved.
• Questions about inheritance patterns. You may simply want to understand how a condition is inherited before deciding whether embryo testing is relevant.

These are conversation starters, not eligibility criteria. Whether PGT-M is suitable for a particular family is a clinical judgement made by the treating team and genetic counsellor after reviewing the history.

Why timing matters: before stimulation, not after

The most practical point in this article is about sequencing. PGT-M usually needs to be planned before ovarian stimulation, because the laboratory must design and validate a test around the family’s specific variant, and because a genetic report is typically needed to define the target. Starting the genetics conversation after an IVF cycle is already underway can create avoidable delays or make PGT-M impractical for that cycle.

For international patients, this timing has a second layer. A remote consultation, a records review, and laboratory set-up all take coordination. If you are comparing clinics or planning travel, treat the genetic counselling step as an early milestone rather than a formality to complete at the airport.

A useful way to think about the sequence:

1. Clarify the family history and whether a specific variant is known.
2. Speak with a genetic counsellor about inheritance and testing options.
3. Confirm with the treating clinic whether PGT-M is appropriate and what the laboratory needs.
4. Only then finalise IVF timing and travel plans.

What the genetic counsellor does — and what the IVF clinician does

Roles are often blurred in online descriptions. A genetic counsellor helps explain inheritance, the implications of a result for you and relatives, and the choices available. The IVF clinician and embryology team manage the medical treatment, the embryo biopsy, and the laboratory testing. The HFEA notes that a treating team and genetic counsellor should discuss history, test design and suitability together — which is a useful model: the genetics and fertility sides inform each other rather than working in isolation.

For a fuller picture of who handles which part of a PGT pathway, see doctor roles in Thai PGT IVF. If you are still deciding which test is relevant, the PGT-A vs PGT-M vs PGT-SR comparison explains the distinctions in more detail.

What to gather before the conversation

Preparation makes a genetic counselling appointment more productive. You do not need a perfect file, but the more precise the information, the more specific the discussion can be.

• The name of the condition, if known, and any genetic report or variant description.
• Which relatives are affected, and how they are related to you.
• Any prior genetic testing results for you, your partner, or an affected child.
• Pregnancy history, including any affected pregnancy or diagnosis.
• Questions you want answered, written down in advance.

If you are organising records for a Thailand clinic, preparing records for PGT-M genetic counselling walks through what international patients typically need to assemble. For the broader clinical picture, how PGT-M works in IVF for genetic disorders is a useful companion read.

Planning PGT-M from abroad: practical coordination

International patients often face a gap between the genetics conversation at home and the IVF clinic in Thailand. Two things help close it: a clear record of the family’s genetic information, and a confirmed understanding of what the Thai laboratory needs before a cycle can be planned.

Coordination support can help with the non-clinical parts of this — organising records, requesting appointments or remote consultations, and planning travel around confirmed dates. It does not replace the genetic counsellor or the treating clinician, who interpret results and advise on suitability. Patients can and should ask their clinicians directly about diagnosis, options, risks, reports and individual chances.

If you are at the stage of comparing what different clinics include in a PGT-M quotation, the eligibility questions for international patients article covers what to clarify before committing. And when results come back, who should explain PGT report findings sets out the questions worth asking about interpretation and next steps.

The bottom line

PGT-M is a targeted embryo test for a known single-gene condition. It is most useful when the genetic target is clear, the laboratory has time to design the test, and the family has had a chance to understand what results can and cannot tell them. If you have a known condition or family history, the genetic counselling conversation is worth starting early — before IVF dates, travel bookings, or stimulation cycles are fixed.

Frequently asked questions

Can PGT-M be arranged after IVF has already started?

It is usually planned before ovarian stimulation because the laboratory needs to design a test around the family's specific variant and a genetic report is typically needed to define the target. Starting later can create delays or make PGT-M impractical for that cycle. Ask your treating clinic about timing for your situation.

Does PGT-M guarantee a healthy child?

No. PGT-M provides information about the specific condition being tested, but it does not guarantee a successful pregnancy or a healthy child. Results should be interpreted with your treating clinician and genetic counsellor.