Do you have inherited diseases in your family? Do you want your unborn child to have no chromosomal abnormalities? Need to improve your chances of IVF success? Preimplantation genetic testing (PGD) will help!
Preimplantation genetic testing of embryos (or preimplantation genetic diagnosis - PGD) is carried out as part of the in vitro fertilization program. PGT (PGD) makes it possible to detect changes in the number of chromosomes and their structure, as well as gene mutations even before the embryos are transferred into the patient's uterine cavity.
This approach makes it possible to prevent pathologies that cannot be determined visually, because even good quality embryos can have genetic disorders.
To determine the presence of indications for PGT (PGD), you need to make an appointment with a geneticist. The specialist will also be able to decide which diagnostic method will be most effective in your case.
PGT of chromosomal abnormalities (PGT-A) involves preimplantation genetic testing (PGD), which allows to identify extra or missing chromosomes in the cell nucleus, as well as areas where genetic material has been lost or, on the contrary, doubled. It is important that the modern technique allows analyze all 46 chromosomes and it is not limited with detection of the most probable disorders.
PGT of monogenic diseases (PGT-M) allows to identify a certain hereditary disease. This method can be recommended if there is a high risk of gene mutations in the unborn child.
Indications for PGT (PGD)
Preimplantation genetic testing (PGD) may be required in the following cases:
- chromosomal abnormalities have previously been identified in children or in the fetus;
- one of the parents is a carrier of a balanced rearrangement in his/her genome;
- there is a high risk of having a child with a monogenic disease in the family (for example, with cystic fibrosis, spinal muscular atrophy, phenylketonuria and other pathologies);
- identified genetic causes of male infertility;
- the mother's age exceeds 40 years (according to statistics, in women of this age category, the proportion of embryos with a normal set of chromosomes is only 20%);
- unsuccessful IVF attempts (two or more) in history;
- pregnancy loss (two or more);
- patients would like to increase the chances of IVF success.
What goals does the PGT (PGD) help to achieve?
PGT for aneuploidy (PGT-A) makes it possible to:
- increase the effectiveness of the in vitro fertilization program (according to statistics, the effectiveness increases by about 27%);
- reduce the chance of early miscarriage, since in 50-70% of cases, termination of pregnancy in the first trimester occurs due to the fact that the embryo has severe genetic pathologies;
- minimize the chance of chromosomal abnormalities in the embryo that will be transferred into the uterine cavity;
- reduce the financial costs of IVF by reducing the number of attempts.
If hereditary pathology is present in the family, PGT for monogenic diseases (PGT-M) allows to:
- transfer only genetically healthy embryos;
- carry out DNA diagnostics of all embryos and vitrify those that do not have genetic pathology in order to transfer only healthy embryos to the patient in the next IVF protocol;
- examine embryos, excluding the possibility of contamination (mixing) of the DNA of the woman and the unborn child. As a result, the risk of misdiagnosis is reduced to zero;
- if you conduct both PGT-A and PGT-M at the same time, it means to exclude both chromosomal abnormalities and hereditary pathologies.
How is preimplantation genetic testing of embryos (PGD embryos) performed
First, specialists must obtain material for research. For this purpose, several embryo cells are biopsied.
At the first stage, it is necessary to destroy the zona pellucida, and only then, using a special microcapillary, extract the cell and fix it for further genetic testing.
PGT of the embryo can be performed using the following techniques:
- NGS (massively parallel signature sequencing);
- array-CGH (comparative genomic hybridization);
Previously, preimplantation genetic testing of embryos was carried out, as a rule, on day 3 of embryo’s development, but now it is proven that a biopsy at this stage significantly reduces the viability of embryos. At the same time, the collection of cells on the 5th day after fertilization does not affect their further development.
Make an appointment with Nova Clinic’s specialist in Moscow and learn more about preimplantation genetic testing of embryos. The consultation price is indicated on the website.