What is Preimplantation Genetic Testing (PGD)?
It is the procedure of only transferring healthy embryos to the mother after conducting genetic testing on the embryos as part of the in vitro fertilization (IVF) application process. In many instances, potential genetic issues have been identified through genetic screenings of either the woman, the man, or both. These screenings can be performed on either parent individually. The procedure for in vitro fertilization starts with the standard steps, which include egg simulation with medication, egg collection, and fertilization. Three days later, the embryo divides into 8 cells. Preimplantation diagnostic steps continue as follows;

1. First, one or two cells are taken from the embryo.

2. Next, the cell DNA is taken and transcribed via polymerase chain reaction (PCR).

3. Finally, molecular analysis of DNA determines whether a problematic gene is present.

After the PGD procedure is performed, the embryo that has been determined to be free of genetic defects is transferred.
Preimplantation genetic diagnosis can help any couple who has a genetic disease or is at risk.

How is the PGT test carried out?

If you have a condition that requires a PGT test, your doctor will recommend this test to you.
Selecting healthy embryos requires a number of steps:
Your embryos are biopsied on the 3rd or 5th day. This process will not harm your embryos.
Genetic test results of your embryos are planned on the 4th or 5th day in fresh trials, and in trophectoderm biopsies, all embryos are frozen and then transferred.
Embryos found to be healthy are reported to be transferred to the expectant mother.
Transferring healthy embryos that do not carry the disease begins a healthy pregnancy for the mother.

Who Should PGD Be Carried Out For?

There are also some special circumstances in which PGT must be used. Those with genetic diseases in their families, in particular, should be cautious about this issue. The following are conditions in which PGT is recommended:

1. In mothers with a history of pregnancy with chromosomal disorders

2. In couples at risk for single gene diseases

3. In mothers who have had more than one miscarriage

4. For expectant mothers over the age of 36

5. In cases of male infertility

6. Couples with a genetic condition in the past

7. Couples who have had unsuccessful IVF treatment several times

The Importance of Genetic Applications in IVF

In addition to infant health and genetic disease diagnosis, these genetic applications in IVF treatment provide the following advantages:

1. It reduces the possibility of multiple pregnancy.

2. It reduces the risk of miscarriage.

3. It reduces the need for medical termination of pregnancy.

4. It increases the chances of getting pregnant.

5. It provides higher success in IVF treatment.

Many of these advantages are due to genetically superior embryos developing more successfully during the developmental stage. This is a very effective safeguard against the occasional failure of IVF treatment due to the existence of these embryos, which adhere better to the mother's uterus, are free of genetic defects, and can maintain their health until birth.

What Kinds of Benefits Does PGD Have?

1. It increases the success of IVF application in appropriate cases.

2. It increases the pregnancy rate.

3. It reduces the risk of pregnancy resulting in abortion (miscarriage).

4. It reduces the need for medical termination of pregnancy.

5. It reduces the rate of multiple pregnancy.

6. It reduces the economic and psychological burdens of repeated failed IVF attempts.

PGD for Single Gene Diseases

When compared to identifying chromosomal abnormalities, preimplantation genetic diagnosis (PGD) for single gene diseases is more challenging because it requires specialized methods and more sophisticated equipment. It is crucially important to know in advance which mutation in the DNA causes the disease in order to use PGD.
In order to examine DNA diseases in embryos, a preparatory phase called the set-up phase is required, which typically lasts between two and three months. The set-up phase is tailored to the mutation in the genetic region that causes the disease in the family. It also includes the identification of family-specific informative markers that reduce the risk of misdiagnosis caused by embryo-stage testing on a single cell.

Since the set-up (pre-preparation) phase is not possible, in couples where the disease cannot be diagnosed, clinically diagnosed but genetic tests are not or cannot be performed, and DNA tests are found to be normal it is not possible to apply the PGT process.