Preimplantation Genetic Testing
Detects potential genetic and/or chromosomal abnormalities in embryos created in vitro
What does Preimplantation Genetic Testing detect?
Preimplantation Genetic Testing (PGT) enables the analysis of embryos obtained during IVF to identify specific genetic and/or chromosomal abnormalities, helping to reduce the risk of transmitting serious hereditary diseases.
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This technique provides relevant genetic information about embryos created through IVF and helps select those with the best prognosis for transfer. This can optimise treatment strategy and contribute to more precise planning.
What is Preimplantation Genetic Testing?
Preimplantation Genetic Testing (PGT) is a technique complementary to in vitro fertilisation (IVF) that allows embryos to be analysed to identify specific genetic and/or chromosomal abnormalities, when there is a clinical indication. This information helps guide embryo selection and personalise the transfer strategy in each case. To do this, several cells are biopsied from the embryo and analysed before transfer to the uterus.
Advantages of PGT
Allows identification of specific genetic and/or chromosomal abnormalities in analysed embryos, contributing to more accurate embryo selection.
Reduces the likelihood of transferring embryos with abnormalities associated with implantation failure, early miscarriage, or certain genetic conditions.
Helps reduce the risk of passing on specific hereditary diseases when there is a clinical indication.
It can help optimise treatment time by prioritising the transfer of embryos with the best chance of resulting in a successful pregnancy. The genetic information obtained helps to reduce the number of less favourable transfers and to plan the process more accurately.
By providing relevant genetic information, it may help optimise transfer strategy, improve planning, and reduce certain associated costs.
Offers additional information to support clinical decision-making and may provide emotional reassurance. Each case must be assessed individually. PGT provides valuable information and may reduce risks in specific cases, but it does not guarantee the absence of all genetic abnormalities or the outcome of pregnancy.
What information does Preimplantation Genetic Diagnosis provide us with?
PGT can be used to study a wide range of specific genetic conditions, depending on the clinical indication and type of analysis performed. This study allows us to assess certain chromosomal or genetic abnormalities, including trisomies, monosomies, and other alterations that may affect embryo development. We distinguish between chromosomal abnormalities and monogenic disorders:
- Structural changes: part of a chromosome may be missing, duplicated, rearranged, or inverted.
- Numerical abnormalities: when there are missing or extra chromosomes. For example, trisomy 21 (Down syndrome) occurs when there are three copies instead of two of chromosome 21. Conversely, Turner syndrome occurs when a female has only one X chromosome (karyotype 45, X0).
Abnormalities in chromosome number and structure are the most common cause of implantation failure and early miscarriage.
Monogenic disorders are mutations affecting a single gene. These mutations can cause inherited genetic diseases such as cystic fibrosis or haemophilia. They result from changes in the DNA sequence of a single gene.
Types de PGD
Preimplantation Genetic Testing includes several modalities used to evaluate different genetic and chromosomal aspects of embryos:
is a preimplantation genetic testing technique that helps us to detect abnormalities in chromosome number, that is, chromosomal losses or gains in embryos, as occurs with trisomy 21 or Down syndrome, where there are three chromosomes instead of two.
This focuses on analysing specific genetic mutations, also known as monogenic mutations, which are associated with hereditary genetic disorders, such as cystic fibrosis.
PGT-M is usually used when there is a known family history or when one or both parents are carriers of the same genetic disorder and there is a risk of passing it on to their offspring.
The aim of this type of PGT is to detect abnormalities in chromosome structure, involving changes to the physical structure of the chromosomes, such as inversions, translocations or deletions. These alterations can cause fertility problems, miscarriages or genetic disorders in offspring.
Who is PGT recommended for?
PGT can be a useful tool in certain IVF treatments, particularly when there is a specific medical indication. It may improve embryo selection and optimise treatment in selected patients. It is especially recommended in the following cases:
Family history of genetic diseases or diagnosed chromosomal abnormalities.
Patients with a history of repeated pregnancy loss.
Patients with failed implantation in two or more IVF cycles.
Patients of advanced maternal age, usually from the age of 38 onwards.
Phases of IVF treatment with PGD
In Vitro Fertilisation (IVF) treatment with Preimplantation Genetic Diagnosis (PGD) involves several phases:
- Personalised ovarian stimulation: from the 2nd day of menstruation, hormonal treatment is started for 10-12 days. During this process, the ovarian response is monitored using ultrasound scans.
- Oocyte collection: When the follicles reach the appropriate size, transvaginal puncture-aspiration is performed to extract the oocytes. This procedure is carried out under anaesthesia with ultrasound monitoring.
2.1-Selection of the best spermatozoa from the couple or the donor. - In vitro fertilisation: The eggs are fertilised in the laboratory with the selected sperm by intracytoplasmic sperm injection (ICSI), where a sperm is injected directly into the egg.
- Embryo culture: The resulting embryos are kept in our laboratory incubators until they reach the blastocyst stage.
- Embryo biopsy: Using aspiration with a micropipette, several embryonic cells are extracted.
- Vitrification of the embryos: The embryos are vitrified in our laboratory while awaiting the PGD results.
- Genetic analysis: The biopsied cells are sent to the genetics laboratory to detect genetic/chromosomal abnormalities.
- Endometrial preparation: Once we have the results, we prepare the uterus so that it is in the best conditions to receive the embryo.
- Transfer of embryos: When the endometrium is prepared, the healthy embryos are identified and one of them is selected. It is then thawed and transferred to the mother’s uterus.
- Pregnancy test: 10 days after the transfer (beta wait) a pregnancy test is performed.
Why choose Tambre for PGT?
At Tambre, PGT is performed at the blastocyst stage (around day 5). At this stage, embryos have both an inner cell mass (future foetus) and an outer layer (trophectoderm, future placenta). The biopsy is performed on the trophectoderm to avoid affecting embryo development.
Before carrying out PGT, it is essential to have a sufficient number of embryos, as this facilitates better embryo selection. For this reason, we perform fully personalised ovarian stimulation to obtain an adequate number of oocytes.
We maintain rigorous quality control throughout the process, ensuring optimal analysis times, accurate results, and ideal embryo preservation conditions.
Thanks to our experience, technology, and dedication, Tambre achieves excellent success rates in PGT.
IVF with PGT: up to 80–90% higher implantation potential
Embryos selected using IVF with PGT have up to 80–90% higher chances of implantation compared to those without PGT.
Specialists in Advanced Reproductive Medicine
Leaders in assisted reproduction in Spain and Europe.
Over 48 years of experience.
We design fully tailored treatments.
- State-of-the-art assisted reproduction laboratory.
- In-house andrology laboratory.
- RI Witness™, for gamete traceability and safety.
- GERI®, embryo incubator.
- Fenomatch, matching donors compatible with you.
- ZyMot-ICSI, advanced sperm selection prior to ICSI.
You will be supported by your own gynaecologist and nurse (except in emergencies), ensuring continuity of care throughout your treatment.
We offer specialised psychological support in reproductive treatments. You will also have access to a dedicated Tambre Care advisor who will guide you and answer your questions throughout the entire process.
We stay with you
Our suppor team is always at your side for whatever you need
Or send us an email to atpaciente@clinicatambre.com
