What is Preimplantation Genetic Testing (PGT)?

Preimplantation Genetic Testing (PGT) is a screening test performed to examine the genetic makeup of embryos created through in vitro fertilization (IVF/ICSI) before they are transferred into the uterus. It is known that one of the most common reasons for IVF failure or lack of pregnancy is abnormal embryo genetics. PGT can reduce the chances of a failed IVF cycle or miscarriage by ensuring that the embryo selected for transfer has the correct number of chromosomes.

Who are good candidates for PGT?

• Individuals over the age of 37 (due to the higher risk of abnormal embryo genetics associated with normal age-related reproductive aging)

• Couples at risk of having a child affected by a hereditary genetic disorder

• Individuals with a history of recurrent miscarriages due to chromosomal abnormalities

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How is PGT performed?

PGT is performed by taking a biopsy from embryos created through IVF/ICSI, typically when the embryos reach the blastocyst stage on day five. A sample of cells is sent to a laboratory for testing. The embryos are frozen before transfer, and the test results are awaited. Once the results are available, in the following menstrual cycle, the uterine lining is prepared either through a natural or hormonal cycle, and the embryo with a normal genetic profile is transferred (FET/DET).

During the IVF process, there is a significant reduction in the number of embryos from fertilized eggs (embryos) to a chromosomally normal blastocyst. Therefore, it is a scientific fact that many eggs and embryos are needed to reach a healthy embryo.

To perform PGT, IVF/ICSI must first be used to obtain embryos. When the embryos reach the blastocyst stage, a biopsy is performed on cells from the outer layer of the embryo (trophectoderm), and the sample is sent for testing. Since the test results take time, the embryos are frozen, and after the results are received, a frozen embryo transfer (FET/DET) is carried out with the embryo that has a normal genetic profile.

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What is PGT-A?

PGT-A is a screening test in which numerical chromosomal abnormalities are sought in a biopsy taken from the trophectoderm or part of the embryo that will form the placenta. This test looks for aneuploidy, a type of numerical chromosomal abnormality, that can affect the embryo's ability to develop into a healthy pregnancy.

This test also provides information about genetic anomalies, such as Down syndrome, which are among the most common genetic disorders in living humans.

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Why is age important in PGT?

Age is extremely important when interpreting the results of this test. Most chromosomal abnormalities come from the egg, and the likelihood of these abnormalities increases with age. As women age, the chances of chromosomal separation errors during egg development also increase. As aging eggs may contain extra or missing chromosomes, genetic issues can arise in embryos produced from these eggs.