What PGT Can and Cannot Tell You About Recurrent Pregnancy Loss

Recurrent pregnancy loss is a frustrating diagnosis, and it is understandable to look for a test that promises an explanation. Preimplantation genetic testing (PGT) is often raised in that search. It deserves a clear answer about scope: PGT examines embryos created in an IVF cycle. It does not investigate why previous pregnancies were lost, and it does not treat the conditions that cause most losses.

That does not make PGT irrelevant. It means the test answers a narrower question than many patients expect, and the value of that answer depends on what else has been assessed.

What PGT actually examines

PGT is an umbrella term for several tests performed on a small sample of cells taken from an embryo, usually at the blastocyst stage. Each type addresses a different question:

• PGT-A looks at chromosome number in the sampled cells. It is used to identify embryos with an abnormal number of chromosomes, a finding called aneuploidy.
• PGT-SR is designed for people who carry a known chromosomal structural rearrangement, such as a balanced translocation. It looks for the specific imbalance that rearrangement could pass on.
• PGT-M is designed for a known single-gene (monogenic) condition that runs in a family.

These are different tests with different purposes, and they are not interchangeable. The comparison of PGT-A, PGT-M and PGT-SR sets out how the questions differ. In a recurrent loss discussion, PGT-A is the type most often raised, because chromosome errors in the embryo are a recognised contributor to early miscarriage. PGT-SR only becomes relevant if a structural rearrangement has actually been found in one partner, and PGT-M only if a specific monogenic condition has been identified.

Why a normal PGT-A result does not close the investigation

PGT-A screens the embryo. It does not examine the uterus, the endocrine system, the immune system, blood clotting, parental chromosomes, or the many other factors that clinical assessment of recurrent loss considers. A couple can have embryos that test as having the expected chromosome number and still experience a miscarriage, because the cause in that pregnancy lay outside the embryo’s chromosome count.

This is the central limit. PGT-A can reduce the chance that an embryo with an abnormal chromosome number is selected for transfer. It cannot lower the risk that comes from non-chromosomal factors, and it cannot tell you why earlier losses happened. A result from an embryo biopsy is not a diagnosis of the couple, and it is not a substitute for the standard workup of recurrent loss, which may include parental karyotyping, imaging of the uterus, and other investigations your clinician considers appropriate.

Where the evidence itself has limits

Even within its own scope, PGT-A is not a certainty machine. Several technical and interpretive limits matter when you are weighing it:

• Sampling. The test reads cells from a biopsy, not the whole embryo. A sampled result does not establish the cell composition of the entire embryo.
• Mosaic results. Sometimes the laboratory reports an intermediate chromosome finding, described as mosaicism. This is inferred from the biopsy findings, and technical factors can contribute to such results. What a mosaic result means for a particular embryo should be discussed with the treating clinician and a genetic counsellor.
• Incorrect or inconclusive findings. PGT-A can produce results that do not reflect the embryo accurately, and some samples do not yield a usable answer.
• Biopsy itself. Removing cells from an embryo carries a risk of damage that can affect further development.
• No guarantee. A PGT result does not guarantee a successful pregnancy or a healthy child.

These points come from regulator and professional-society patient information, and they are general. They are not a prediction about your embryos or your chances. The guide to what PGT-A screens and who it may help covers the test’s purpose in more detail.

Separating the embryo factor from other factors

A useful consultation does not ask “should we do PGT?” in isolation. It asks your clinician to separate two questions: what role, if any, embryo chromosome problems may have played in your losses, and what other factors have been assessed or still need assessment. Those are different lines of enquiry, and only the second can address causes such as uterine, endocrine, immune or clotting-related conditions.

You can ask directly:

• Which investigations have already been done for our losses, and which are still outstanding?
• Has parental karyotyping been performed, and does it change whether PGT-SR or PGT-M is relevant for us?
• If we use PGT-A, what would a normal result change in our plan, and what would it not change?
• How would a mosaic or inconclusive result be handled in our case?
• What alternatives exist if we decide against embryo testing?

These are clinical questions, and they belong with a licensed clinician who can see your history. A coordination service can help you organise the conversation and the records, but it does not interpret results or advise on treatment.

Records worth bringing to a PGT conversation

Recurrent loss discussions go better when the history is documented rather than recalled. A practical record set includes:

• A dated list of previous pregnancies and losses, with gestational age where known.
• Any prior loss workup: blood tests, imaging, uterine assessment, and pathology reports if tissue was examined.
• Parental karyotype results, if performed.
• Any genetic counselling letters or reports of a known familial condition.
• Current medication list and relevant past medical history.

Approximate dates are fine if exact ones are not available; write down what you know and mark what is uncertain. Do not stop or change any medication in preparation for a consultation unless your prescribing clinician tells you to.

Planning the conversation, including from abroad

If you are considering treatment in Thailand, the practical work starts before any appointment. A short written summary of your history, a question list, and a clear note of which records are still missing will make a remote consultation more useful. It also helps to ask, in writing, what the hospital needs from you, in what format, and whether a remote discussion is possible before travel.

For patients comparing options, it can help to read broadly about how PGT is discussed for recurrent loss in Thailand, for example this cautious guide to PGT and recurrent miscarriage, and to keep provider shortlists as a separate research task rather than a substitute for clinical assessment. If you want a starting point for that separate comparison, the countrywide shortlist of IVF hospitals and clinics is an editorial overview, not evidence that any provider produces better outcomes.

Thailand PGT can help organise records, prepare a question list, request appointments or remote consultations, and coordinate follow-up communication after you return home. Scope and any fees are confirmed individually, and clinical decisions remain with your treating clinicians.

Frequently asked questions

Does PGT-A prevent miscarriage?

No. PGT-A screens embryos for chromosome number, so it can reduce the transfer of embryos with an abnormal count. It does not prevent miscarriage caused by factors outside the embryo's chromosomes, and it cannot guarantee a pregnancy or a healthy child.

Should everyone with recurrent pregnancy loss have PGT?

There is no single answer that applies to everyone. Whether PGT is appropriate depends on your history, what investigations have already been done, and what you and your clinician are trying to learn. It is not a replacement for the standard assessment of recurrent loss.