FET and PGT: Two Key Pillars of Modern IVF

By Dr. Athanasios Garavelas

In modern IVF, success does not depend only on the creation of embryos. It increasingly depends on when the embryo transfer takes place, under what conditions the endometrium is prepared, and, in selected cases, which embryo is chosen for transfer.

In this context, two concepts have gained particular importance: frozen embryo transfer, known as FET (Frozen Embryo Transfer), and preimplantation genetic testing, known as PGT (Preimplantation Genetic Testing).

These are not merely technical options. They are tools that allow the fertility specialist to organize treatment with greater precision, better timing, and a clearer strategy.

What does FET offer?

Frozen embryo transfer allows the egg retrieval cycle to be separated from the embryo transfer cycle. The embryos are frozen using modern vitrification techniques and transferred in a subsequent, appropriately prepared cycle.

This is particularly valuable because it makes it possible:

• to perform the transfer when the endometrium is in the most suitable possible condition;
• to reduce the pressure for immediate transfer in the same stimulation cycle;
• to avoid embryo transfer when there is an increased risk of ovarian hyperstimulation;
• to better organize treatment when genetic testing of the embryos is required.

In simple terms, FET offers time, flexibility, and better therapeutic synchronization.

Why has FET changed the way treatment is planned?

The ability to freeze embryos and transfer them in a subsequent cycle has substantially changed the philosophy of IVF. Treatment no longer needs to be completed hastily within the same cycle. It can be organized based on each woman’s individual data, the hormonal environment, and the requirements of the specific case.

Especially when the endometrium is not considered ideal, or when hormonal stimulation is intense, the choice of FET allows for a more controlled approach. The goal is not simply to transfer an embryo, but to transfer it at the right time.

The essential connection between FET and PGT

FET and PGT often work complementarily. In order to perform genetic testing on embryos, time is required for biopsy, laboratory analysis, and the issuing of results. Cryopreservation makes this process possible without putting pressure on the timing of the embryo transfer.

Thus, the transfer can take place in a subsequent cycle, after:

• the embryos have been evaluated;
• the genetic analysis has been completed, where indicated;
• the endometrium has been appropriately prepared;
• the most targeted transfer strategy has been selected.

This is the major significance of combining FET and PGT: it allows for a more organized, more individualized, and more evidence-based therapeutic approach.

Fresh embryo transfer vs frozen embryo transfer

Fresh embryo transfer is performed in the same cycle as egg retrieval. Frozen embryo transfer is performed in a subsequent cycle, after vitrification and storage of the embryos.

The significance of FET is that it allows the physician not to base embryo transfer exclusively on the stimulation cycle. When there is an increased risk of ovarian hyperstimulation, when hormonal conditions are not considered optimal, or when time is required for preimplantation genetic testing, the transfer can be scheduled at a later stage, in a more controlled setting.

This is also why FET has acquired a central role in modern IVF: it is not simply an alternative to fresh embryo transfer, but a tool that enables safer and more targeted treatment planning. The choice remains individualized, but in many cases FET makes it possible to perform the embryo transfer at the most appropriate time and, where indicated, after completion of PGT.

Modern IVF is a strategic treatment

IVF today is not a standardized procedure with only one path. It is a treatment planned step by step. FET allows for better timing. PGT, where indicated, adds critical information. Together, they can contribute to more comprehensive planning of the treatment attempt.

The aim is not to apply every available technique, but to select the appropriate techniques for the right woman, at the right time.

When treatment is properly planned, hope gains direction

In assisted reproduction, every detail matters. Proper evaluation, precise timing, and the selection of the appropriate tools for each individual case are what can transform a treatment attempt into a journey with clear direction and meaningful prospects toward motherhood.