Preimplantation Genetic Testing (PGT) | Prof. Dr. İkbal Kaygusuz

Reproductive Genetics and Preimplantation Genetic Testing (PGT)

Prof. Dr. İkbal Kaygusuz Last reviewed: 25 September 2026 2 min read

In short: Preimplantation genetic testing (PGT) examines a few cells taken from IVF embryos before transfer. It is used for couples with a known single-gene disorder (PGT-M) or chromosomal rearrangement (PGT-SR), and in selected cases to screen chromosome number (PGT-A). Genetic counselling beforehand is important.

Why does reproductive genetics matter?

Genetic factors play a role in some cases of infertility, recurrent pregnancy loss and early decline in ovarian reserve. Combining obstetrics and gynecology with medical genetics helps decide which tests are truly needed, interpret results correctly and give families accurate information.

Genetic assessment before pregnancy

Carrier screening: recommended for consanguineous couples or families with inherited conditions such as spinal muscular atrophy, thalassaemia or cystic fibrosis.
Karyotype: considered in recurrent pregnancy loss, severe sperm abnormalities or premature ovarian insufficiency.
Fragile X and other tests: may be considered with markedly reduced ovarian reserve at a young age.

Types of PGT

PGT-M (single-gene disorders)

Embryos are tested for an inherited condition the couple is known to carry, and unaffected embryos are selected for transfer.

PGT-SR (structural rearrangements)

Used when a partner carries a balanced translocation or inversion, to avoid transferring embryos with unbalanced chromosomes.

PGT-A (aneuploidy screening)

Screens embryos for abnormal chromosome numbers. It is not recommended routinely and is considered in selected situations such as advanced maternal age or recurrent implantation failure.

How is PGT done?

IVF embryos are usually grown to the blastocyst stage (day 5 or 6). A few cells are taken from the outer layer that will form the placenta and the embryos are frozen. After the results, a suitable embryo is transferred in a later cycle.

Limitations

PGT is highly accurate but not definitive; mosaicism can complicate interpretation. Prenatal screening or diagnostic testing is still recommended in pregnancies after PGT, and genetic counselling is an essential part of the process.

Where procedures are performed
IVF procedures are performed at the licensed Anlaşmalı Tüp Bebek Merkezi. Assessment, planning and follow-up take place at the clinic.

Frequently Asked Questions

Can PGT be used to choose the baby's sex?

No. Under Turkish regulations, sex selection for non-medical reasons is prohibited. Sex-linked inherited diseases require separate medical assessment.

Is genetic testing needed in consanguineous marriages?

Consanguinity increases the chance of recessive disorders. Genetic counselling and carrier testing before pregnancy are recommended, especially with a family history.

Does taking cells harm the embryo?

A few cells are taken from the outer layer that forms the placenta. In experienced laboratories the effect on embryo development is limited.

Sources

ESHRE PGT Consortium. Good practice recommendations for preimplantation genetic testing, 2020.
T.C. Sağlık Bakanlığı, Üremeye Yardımcı Tedavi Uygulamaları ve Üremeye Yardımcı Tedavi Merkezleri Hakkında Yönetmelik.

The information on this website is for general information only and does not replace a medical consultation.

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