# PGT-M : testing embryos for an inherited condition > What PGT-M is, who it is generally used for, how a family-specific test is prepared before an IVF cycle, and its risks and limits, based on ESHRE and HFEA. Source: https://www.ghinashami.com/en/interests/pgt-m/ Updated: 2026-10-13 Step 3 of 4 · Assisted reproduction When a serious genetic condition is known in a family, embryos created through IVF can be tested for that specific condition before one is transferred. This is PGT-M (preimplantation genetic testing for monogenic conditions), previously called PGD, and it begins with genetic counselling well before a cycle. - 4 min read - Reviewed 13 October 2026 - 7 references ## Who it is generally used for PGT-M is for people who already know that a serious genetic condition runs in their family and want to reduce the chance of passing it on. A doctor may discuss it when, for example: - both partners carry the same recessive condition, such as cystic fibrosis, so that each pregnancy has a one-in-four chance of being affected - one partner has a dominant condition that can be passed on to children - the woman carries an X-linked condition, such as haemophilia - a previous child is affected, or a previous pregnancy was ended because of a serious genetic condition - carrier screening or other genetic testing has already identified the gene change; see [genetic history and testing](https://www.ghinashami.com/en/interests/genetic-testing/) Recessive conditions are more common when partners are related by blood. For these couples, genetic testing comes first: PGT-M generally becomes possible only once the specific gene change in the family has been identified. ## How a PGT-M cycle runs **Genetic counselling and the family work-up come first.** A clinical geneticist or genetic counsellor confirms the diagnosis, reviews the family tree, and explains the options, the expected time-frame and the limits of testing. This step decides whether PGT-M is possible. **A test is prepared for the family.** The laboratory designs and checks a test for the specific gene change, usually using DNA from both partners and from relatives whose status is known. This preparation is usually completed before ovarian stimulation starts. **Then an IVF cycle.** Stimulation, egg collection and usually ICSI, which avoids extra sperm contaminating the test, are followed by culture to the blastocyst stage and the removal of a few cells from each embryo. The embryos are usually frozen while the laboratory reports, and an embryo found to be unaffected is transferred later; see [IVF and ICSI](https://www.ghinashami.com/en/interests/ivf-icsi/). PGT-M reduces the chance of passing on the condition it was designed to detect. It does not test for other conditions, it does not ensure a pregnancy, and not every cycle produces an unaffected embryo. Prenatal diagnosis should still be offered in any pregnancy that follows. ## Questions worth asking your doctor 1. 1 Has the gene change been confirmed? A report from years ago or from another country may need to be confirmed before a test can be designed around it. 2. 2 How long will the preparation take? The family work-up and the design of the test happen before the IVF cycle; ask for the expected time-frame. 3. 3 How does our fertility affect the plan? The number of embryos available to test depends on the ovarian reserve and the sperm, so a fertility assessment is part of planning, even for couples who conceive easily. Dr. Ghina Shami ## Risks and limits **An IVF cycle is needed.** PGT-M carries the risks of IVF, including ovarian hyperstimulation and multiple pregnancy if more than one embryo is transferred; see [IVF and ICSI](https://www.ghinashami.com/en/interests/ivf-icsi/). **Harm to the embryo.** Some embryos may be damaged by the biopsy and then cannot be used. **Wrong findings.** PGT-M is not completely accurate. In a small number of cases the test does not work or gives the wrong answer, for example when one copy of the gene is not detected (allele drop-out) or when outside DNA contaminates the sample. This is why prenatal diagnosis is offered to everyone who becomes pregnant after PGT. **No suitable embryo.** Some cycles produce no unaffected embryo that can be transferred. **Personal and ethical weight.** Testing involves decisions about embryos, including that affected embryos are not transferred, and it is not the right choice for everyone. Counselling is part of the process. ## Common questions **Is IVF needed if we have no fertility problem?** Yes. Embryos can be tested only if they are created in the laboratory, so a full IVF cycle with stimulation, egg collection and ICSI is needed even when natural conception is easy. **What is the difference between PGT-M and PGT-A?** PGT-M looks for one specific inherited condition known in the family. [PGT-A](https://www.ghinashami.com/en/interests/pgt-a/) counts chromosomes, and NICE advises against using it to improve live birth rates. Whether it has any role in your case is something your doctor can advise on. **What if no unaffected embryo is found?** It can happen, and it is discussed before starting. Depending on the condition and the number of eggs collected, the options may include another cycle, a natural pregnancy with prenatal diagnosis by chorionic villus sampling (CVS) or amniocentesis, or stopping. A genetic counsellor can go through them with you. **Evidence basis:** This page is based on ESHRE good practice recommendations, which rest largely on expert consensus, on NICE guidance, and on information from the HFEA and NHS England's Genomics Education Programme. ## References 1. Pre-implantation genetic testing for monogenic disorders (PGT-M) and Pre-implantation genetic testing for chromosomal structural rearrangements (PGT-SR), HFEA (2026) — [hfea.gov.uk](https://www.hfea.gov.uk/treatments/embryo-testing-and-treatments-for-disease/pre-implantation-genetic-testing-for-monogenic-disorders-pgt-m-and-pre-implantation-genetic-testing-for-chromosomal-structural-rearrangements-pgt-sr/) 2. I have a genetic disease in my family, HFEA (2016) — [hfea.gov.uk](https://www.hfea.gov.uk/i-am/i-have-a-genetic-disease-in-my-family/) 3. ESHRE PGT Consortium good practice recommendations for the detection of monogenic disorders, ESHRE, Human Reproduction Open (2020) — [doi:10.1093/hropen/hoaa018](https://doi.org/10.1093/hropen/hoaa018) 4. ESHRE PGT Consortium good practice recommendations for the organisation of PGT, ESHRE, Human Reproduction Open (2020) — [doi:10.1093/hropen/hoaa021](https://doi.org/10.1093/hropen/hoaa021) 5. ESHRE PGT Consortium and SIG Embryology good practice recommendations for polar body and embryo biopsy for PGT, ESHRE, Human Reproduction Open (2020) — [doi:10.1093/hropen/hoaa020](https://doi.org/10.1093/hropen/hoaa020) 6. Autosomal recessive inheritance, NHS England Genomics Education Programme (GeNotes) (2025) — [genomicseducation.hee.nhs.uk](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/autosomal-recessive-inheritance/) 7. Fertility problems: assessment and treatment, NICE (guideline NG257) (2026) — [nice.org.uk](https://www.nice.org.uk/guidance/ng257) Written and reviewed by [Dr. Ghina Shami](https://www.ghinashami.com/en/about/), Consultant, Reproductive Medicine and Infertility · 13 October 2026 · [How these pages are prepared](https://www.ghinashami.com/en/legal/#accuracy)