Pre-implantation genetic testing (PGT-A / PGT-M) (Pre-implantation genetic testing of embryos)

What is pre-implantation genetic testing (PGT-A and PGT-M)?

Pre-implantation genetic testing means taking a few cells from an IVF embryo (usually at about day 5, the blastocyst stage) and testing them in the laboratory before deciding which embryo to put back into the womb. It is an extra step added on to standard IVF or ICSI.

There are two very different tests that sound similar but are not the same thing. PGT-M (for monogenic, or single-gene, conditions) looks for a specific inherited condition that runs in your family, such as cystic fibrosis or Huntington's disease. PGT-A (for aneuploidy) simply counts the chromosomes in the embryo to see whether the number looks normal.

This difference matters a lot. PGT-M is an established part of care for couples at high risk of passing on a serious genetic condition, and the conditions tested must be specifically licensed by the HFEA. PGT-A is rated by the HFEA as a treatment 'add-on', and for most people there is no good evidence that it improves the chance of having a baby. The national guidance body NICE also advises that PGT-A should not be offered as a way to try to improve the chance of a live birth.

No genetic test of an embryo can promise a healthy baby. It looks at the cells removed at one moment in time, the result can be wrong, and an embryo that looks abnormal on the test can sometimes still be healthy.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

PGT-M versus PGT-A — they are not the same

If a clinic offers you 'genetic testing of embryos', ask clearly which test they mean and why. The two have very different evidence and very different reasons for use.

Preparing for your treatment

• Ask the clinic to be clear in writing whether they are offering PGT-M, PGT-SR or PGT-A, and exactly why it is being recommended for you.
• For PGT-M, expect genetic counselling first, and a check that the specific condition is licensed by the HFEA; NHS funding has strict criteria, so ask about referral.
• For PGT-A, ask to see the HFEA traffic-light rating and ask what difference the result would actually make to your chance of a baby.
• Discuss how many embryos you are likely to have, as testing reduces the number available and some embryos may not survive the biopsy or freezing.
• Talk through what you would do with a 'mosaic' or 'abnormal' result before you start, not after.
• Make sure you understand this usually means a frozen embryo transfer in a later cycle, not a fresh transfer.
• Ask whether you are being asked to pay extra and whether the same money might be better spent on further standard treatment cycles.

What happens

PGT is added on to a normal IVF or ICSI cycle. After egg collection and fertilisation, embryos are grown in the laboratory, usually to the blastocyst stage at about day 5 or 6. An embryologist then removes a small number of cells from each suitable embryo.

The embryos are frozen while the cells are sent for genetic analysis. For PGT-M the laboratory looks for the specific inherited condition; for PGT-A it counts the chromosomes. Results usually take from a few days to a couple of weeks.

A report then says which embryos are suitable to transfer. In a later cycle, one suitable embryo is usually thawed and transferred. Not every cycle produces an embryo that can be tested or that passes testing, so some people finish a cycle with no embryo to transfer.

Is this treatment right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

The biggest issue with PGT-A is not physical harm but false promise: for most patients there is no good-trial evidence it improves the chance of a baby, and it can leave you with fewer embryos. PGT-A results are also not black-and-white — 'mosaic' embryos can still lead to healthy babies. Ask your clinician what the test would change for you, what a mosaic or abnormal result would mean, and whether the condition (for PGT-M) is HFEA-licensed.

Published figures to discuss

Reliable numbers for PGT depend heavily on which test is meant, the patient's age and how many embryos they have. For PGT-A in particular, the headline message from good trials is the absence of benefit for most patients, not a precise complication rate, so we avoid giving misleading percentages.

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

What happens afterwards

There is no physical recovery from the test itself, which is done on embryos in the laboratory. The main thing afterwards is waiting for the genetic report and deciding which embryo to transfer.

• A tense wait of days to a couple of weeks for the genetic report
• Feeling disappointed if fewer embryos are suitable than you hoped
• Mixed feelings about a 'mosaic' or inconclusive result
• Needing time to decide which embryo to transfer and when

Aftercare

• Ask for the result, and the report, to be explained clearly, including what 'mosaic' or 'inconclusive' means.
• Do not make a final decision about discarding embryos under pressure or in a single appointment.
• For PGT-M, keep your genetic counselling contact in case you have further questions.
• Check what storage arrangements and consent apply to any remaining frozen embryos.
• Ask what the plan is if this cycle does not lead to a transfer or a pregnancy.
• Keep a written copy of which embryos were tested and the results.

• Written confirmation of which test you are having (PGT-M, PGT-SR or PGT-A) and why
• For PGT-M: genetic counselling appointment booked and HFEA licensing confirmed
• A clear plan for what a mosaic, abnormal or inconclusive result would mean
• Understanding that a frozen transfer in a later cycle is likely
• A copy of the storage and consent paperwork for frozen embryos
• The clinic's contact for questions about your results

⚠ Get urgent help if…

• Severe abdominal pain, bloating, breathlessness or reduced urine after egg collection (possible OHSS) — seek urgent advice
• Heavy vaginal bleeding after egg collection or transfer
• Fever or feeling generally unwell after any procedure
• Severe or one-sided pain, shoulder-tip pain or feeling faint in early pregnancy (possible ectopic) — seek urgent help
• Feeling pressured to discard embryos or pay for tests you do not understand — pause and seek independent advice

Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your specialist gives you.

Results & realistic expectations

For PGT-M and PGT-SR, a useful result is identifying an embryo that does not carry the specific condition or imbalance being tested for. For PGT-A, a 'normal' (euploid) result means the chromosomes counted looked normal in the cells that were removed — it does not prove the embryo is healthy, and it does not guarantee a pregnancy or a baby.

Results can be wrong in either direction, and 'mosaic' results sit in a grey zone: embryos labelled mosaic have gone on to become healthy babies. A genetic test is one piece of information, not a guarantee.

Tested embryos that are suitable can usually be frozen and stored for use in future cycles, subject to consent and storage time limits. A result reflects the embryo at the time of testing; it does not change, but how much weight to give it (especially a PGT-A or mosaic result) is a decision to make with your clinician.

Related tests, treatments or support

PGT is always combined with IVF or ICSI, because embryos have to be created and grown in the laboratory before they can be tested. It should not be bundled together with other unproven add-ons; each one should be justified on its own evidence.

Follow-up & long-term care

After testing you will have a discussion about which embryos are suitable and a plan for a frozen embryo transfer. For PGT-M, follow-up should include genetic counselling and clarity about what the result means for any pregnancy and for future children.

• Keep storage and consent paperwork for frozen embryos up to date.
• Note storage time limits and any renewal arrangements.
• Keep genetic counselling contacts for PGT-M in case questions arise later.

Repeat, follow-on and what comes next

• PGT-A results can be inconclusive or 'mosaic', sometimes needing re-biopsy or a careful decision about whether to transfer.
• A cycle can end with no embryo suitable for transfer, meaning another full cycle may be needed.
• Results do not change, but the advice on how to act on a mosaic or borderline result may evolve.

Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.

What good aftercare looks like

• A clear, unhurried discussion of results, including what mosaic and inconclusive mean.
• Genetic counselling for PGT-M before and after testing.
• A written plan for a frozen transfer and for the situation where no embryo is suitable.
• Honesty about the limits of the test and no promise of a healthy baby.
• A named contact for questions about results and stored embryos.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

• Whether the test is PGT-M, PGT-SR or PGT-A, as the laboratory work differs
• The cost of the IVF or ICSI cycle the test is added to
• The number of embryos biopsied and analysed
• Setting up a bespoke PGT-M test for a specific family condition
• Freezing and storage of embryos while you wait for results
• Genetic counselling and any further consultations
• Whether a frozen transfer cycle is included or charged separately

• Which test is included (PGT-M, PGT-SR or PGT-A) and the evidence for it
• The cost of the underlying IVF/ICSI cycle and of the biopsy and analysis
• Embryo freezing and storage fees, and storage time limits
• Genetic counselling fees, where relevant
• Whether a later frozen embryo transfer is included
• What happens, and what is charged, if no embryo is suitable to transfer
• Cancellation policy and what is refunded if the cycle stops early

On the NHS? PGT-M for a known serious inherited condition can be NHS-funded if you meet strict criteria and the condition is HFEA-licensed; PGT-A is generally not NHS-funded and is sold privately as an add-on. NHS and HSC funding rules differ across England, Scotland, Wales and Northern Ireland and can change over time, so ask the relevant NHS/HSC fertility commissioner or clinic to confirm your current eligibility.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

Consent traps and marketing red flags

These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.

Choosing a specialist safely

• Check the specialist is on the GMC Specialist Register for this area.
• Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
• You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
• Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
• You're entitled to your total cost in writing — including any follow-up — before you decide.

How Vuemedics verifies every consultant →

Take this to your consultation. A good specialist will welcome every one of these.

• Are you offering PGT-M, PGT-SR or PGT-A, and exactly why for me?
• What is the HFEA traffic-light rating for this test, and what will the result actually change for my chance of a baby?
• For PGT-M: is the condition HFEA-licensed, and could this be NHS-funded?
• What would a 'mosaic', abnormal or inconclusive result mean, and what would you advise then?
• How many embryos am I likely to have, and how many might be lost to testing or freezing?
• Am I being charged extra, and would that money be better spent on further standard treatment?
• Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
• Will you be the specialist who carries out my treatment, and who looks after me afterwards?
• What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
• What does a realistic result look like — and what can this treatment not achieve?
• What are my options, including waiting, doing nothing for now, or choosing a different approach?
• Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
• What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Find a verified specialist for pre-implantation genetic testing (pgt-a / pgt-m)

Every consultant is GMC-checked and independently reviewed. Search by postcode and distance, or switch to a map. Ordered by rating, relevance and recency — never by who pays.

How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: HFEA — PGT-A (rating and evidence) HFEA — Treatment add-ons and the traffic-light system HFEA — PGS (PGT-A) rating now red following review NICE NG257 — Fertility problems: assessment and treatment NHS Genomics Education — Pre-implantation genetic testing Genetic Alliance UK — Pre-implantation genetic testing NICE NG257 — procedures used during IVF (PGT-A) NHS inform (Scotland) — infertility and fertility access NHS Wales — specialist fertility services commissioning policy Belfast Trust — Regional Fertility Centre (Northern Ireland)

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.