Fertility Treatments
Every embryo has a story, and our testing helps you understand it. Through careful genetic testing, we provide valuable insight into embryo health, help minimise risk and support your fertility journey with clarity and care.
Preimplantation Genetic Testing (PGT) is an advanced procedure used as part of IVF that analyses a small sample of cells from an embryo before transfer. It gives you and your fertility team valuable information about the chromosomal makeup of each embryo, helping to identify any that are unlikely to implant successfully or may result in miscarriage, supporting more informed decisions about which embryo to transfer.
1. PGT-A (Aneuploidy): detects embryos with abnormal chromosome numbers to reduce miscarriage risk and implantation failure.
2. PGT-M (Monogenic): Identifies embryos free of specific single-gene disorders, preventing inherited diseases.
3. PGT-SR (Structural Rearrangements): Detects chromosomal rearrangements that could cause miscarriage or genetic disorders.
PGT may be recommended for a number of reasons.
Your fertility specialist will advise whether PGT is appropriate based on your individual circumstances, including age and family history.
Our Preimplantation Genetic Testing (PGT) process helps provide insight into your embryos and supports your IVF journey.
The results we gain from testing helps guide your IVF plan and can improve the chances of a successful pregnancy, giving you clarity and confidence at each step of your journey.
*PGT-A/PGT-M process overview
Fertility treatment is used to create multiple embryos.
Embryos grow for five to six days until they reach the blastocyst stage.
A highly trained embryologist carefully removes for genetic testing 5–7 cells from the outer layer of the embryo that would become the placenta.
The embryos are safely frozen while testing is carried out.
Embryos are selected for transfer based on their chromosomal status - identifying those that are sufficiently balanced or unaffected by a specific genetic condition - as well as their overall quality and appearance (morphology), as assessed by our embryologists.
Important considerations
Embryo biopsy is a very safe procedure, with less than a 1% risk of damage. However, not all embryos are suitable for biopsy, and if testing shows an embryo is aneuploid, it will not be recommended for transfer.
By identifying embryos with chromosomal imbalances, PGT-A can increase the chance that implantation will succeed and reduce the risk of miscarriage. Up to 50% of miscarriages are caused by chromosomal abnormalities. It can also improve the chances of a healthy singleton pregnancy, offering reassurance as you plan your family.
Beyond these benefits, the insights gained through testing can guide your IVF plan, helping your specialist tailor your treatment for the best possible outcome.
In some cases, if no suitable embryos are identified, your specialist will talk you through what this means and the options available to you.
Our Embryo Genetic Testing Success in Numbers
Between 2019 and 2024, we have supported many patients using PGT-A, helping them make informed decisions and optimise their chances of success. Our patients undergoing PGT-A had an average age of 38.1, reflecting the importance of embryo genetic testing in maximising the likelihood of a healthy embryo transfer.
When a euploid embryo is identified and transferred, patients achieve live birth rates comparable to those under 37 or using donor eggs, highlighting the benefit of selecting embryos with the best genetic potential.
The chance of finding a euploid embryo decreases as age increases. Based on our clinic data:
| Age Group | % of Embryos Returning as Euploid |
|---|---|
| <35 | 50% |
| 35–37 | 44% |
| 38–39 | 33% |
| 40–42 | 21% |
| 43–44 | 11% |
Age also affects the number of eggs needed to identify at least one euploid embryo:
| Age Group | Eggs Required per Cycle to obtain one euploid |
|---|---|
| <35 | 5 |
| 35–37 | 6 |
| 38–39 | 8 |
| 40–42 | 14 |
| 43–44 | 34 |
These numbers illustrate why PGT-A can be particularly valuable, helping patients identify embryos with the highest potential while planning their treatment with clarity.
Want to learn more? Visit our Success Rates page to explore the latest outcomes.
Genetic counselling is here to help you understand your results and feel confident about your choices:
Testing with PGT-A or PGT-M can improve your chances of success, but it does not guarantee a baby.
Sometimes embryos are found to be mosaic (a mix of normal and abnormal cells). Your doctor will guide you through what this means for your treatment and help you understand your options.
Genetic counselling is there to ensure you feel supported and informed, giving you confidence in every step of your fertility journey.
PGT-M is a type of embryo genetic testing recommended for couples who are at risk of passing on serious inherited conditions. It allows you to make informed decisions while reducing the uncertainty and emotional stress that can come with prenatal testing or the possibility of pregnancy termination.
This testing can only be done for conditions approved by the HFEA, with common examples including sickle cell anaemia and cystic fibrosis, and it is often used alongside PGT-A to help select the healthiest embryos for transfer. Reported success rates are encouraging, with over 65% per transfer and up to 95% after three transfers, depending on the woman’s age.
Understanding the costs involved is an important step when considering Embryo Genetic Testing. We aim to provide clear, transparent pricing so you know what to expect from the start.
For a full breakdown of costs and what’s included in our Embryo Genetic Testing treatment plans, please get in touch with our team.
The HFEA has listed PGT-A as green on their traffic light system as it has been shown to reduce the risk of miscarriage. Other possible benefits of PGT-A remain under review because of limited evidence this treatment works well for all patients. This is why we only recommended PGT-A for women in a specific age range and on a case-by-case basis. For more information on the benefits, risks and the nature of clinical evidence regarding PGT-A, please read here.
Chromosome aneuploidy describes the condition in which there is an incorrect number of chromosomes in an embryo. In a normal embryo there are 22 pairs of chromosomes plus two sex chromosomes. One of each pair is inherited from our mother and father in the egg and sperm in fertilisation. Most aneuploidies are lethal to the embryo and are a major cause of IVF failure and miscarriage. In rare cases, they result in abnormal pregnancy and an affected child. The majority of aneuploid embryos (90%) occur when eggs with extra or missing chromosomes are fertilised. Sperm cells may also cause aneuploidy but the prevalence is usually lower (around 10%).
Genetic testing of embryos, such as PGT-A, can help identify embryos that are chromosomally balanced, which may reduce the risk of miscarriage. However, it does not guarantee a pregnancy or prevent all miscarriages, because other factors can also affect pregnancy outcomes. The results give your fertility team better information to select embryos with the best chance of success, helping you make more informed decisions during your IVF journey.
A mosaic embryo is one that has a mix of normal (euploid) and abnormal (aneuploid) cells. A mosaic result doesn’t give a clear “yes” or “no” about whether an embryo will lead to a healthy pregnancy. Some mosaic embryos can still develop normally, while others may not. This information helps your fertility team make more informed decisions about which embryos to transfer.
This can happen if embryos have chromosomal imbalances or carry the genetic condition being tested for. While this can be disappointing, the results provide important information that helps guide your next steps in IVF and family planning. Your fertility specialist will discuss alternative options with you, such as trying another cycle, using donor eggs, or exploring other personalised strategies to support your journey.
Yes. Embryo biopsy is a very safe procedure when performed by experienced embryologists. Only a few cells are carefully removed from the blastocyst, and in our expert hands the risk of any damage to the embryo is very low - less than 1%. After the biopsy, embryos are frozen while testing is completed and those suitable for transfer are used in your IVF plan.
PGT can give you valuable information about your embryos and help guide your IVF journey, but it does not improve the quality of your embryos or guarantee a pregnancy or a baby. It can improve the chances of transferring a chromosomally balanced embryo, potentially reducing the risk of miscarriage and increasing the likelihood of a healthy pregnancy, but many other factors - such as age, egg quality, sperm quality and overall health - also affect IVF success.
At London Women’s Clinic, we combine experience, innovation, and compassionate care to give you the best chance of success:
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Every fertility journey is unique and understanding your embryos can make a real difference. Schedule a Fertility Health Assessment today to explore if embryo genetic testing could support your chances of a healthy pregnancy.
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David Williams OBE, Chair of JD Healthcare Group, has retired after more than 20 years of transformative leadership, guiding the growth of London Women’s Clinic from a single Harley Street clinic to over 20 UK locations. He leaves a lasting legacy of clinical excellence, mentorship, and dedication to both colleagues and patients.
On Saturday 18th April, 600 people walked through the doors of the De Vere Grand Connaught Rooms in London for the fourth Familymakers Show — and the energy in the room felt like something that has been a long time in the making. Because in many ways, it has.
"If she hadn't made that phone call, I would never have known that embryo had a chance..." At 46, having already been through three IVF cycles and preparing to begin donor egg treatment, Ella had almost given up on the idea of becoming a mother using her own eggs. Then an embryologist at London Women's Clinic made a call that changed everything. This is the story of one frozen embryo, a DNA swab sent from overseas, and the four-year-old girl who is now the light of her mother's life — and why advances in genetic embryo testing are making the seemingly impossible possible.
Michelle was 39 when she walked into a London Women's Clinic open day, already certain of one thing: she didn't want to waste time. What followed was two IVF cycles, a devastating first round where no embryos were chromosomally normal, a mosaic result, and an embryo that came back from retesting as something extraordinary — euploid, chromosomally normal, and ready to become her daughter.
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