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Groundbreaking techniques have been developed In IVF treatments over the years in parallel with the advances in medicine. Among them, PGD is perhaps one of the most remarkable one. Medical advances has allowed ensuring the embryo to be transferred is genetically healthy.

PGD plays a vital role in the advancement of IVF treatments in Cyprus. PGD practices in Cyprus also allow the sex of the baby to be transferred to be known in advance. Gender selection is necessary in some sex chromosome inherited diseases.

Preimplantation genetic testing (diagnosis or screening) is currently used worldwide for the selection of euploid embryos (having a normal number of chromosomes). Transfer of chromosomally healthy embryos increases embryo implantation, clinical pregnancy and live birth rates. IVF success rates depend on certain elements: development of the ovaries, egg collection, culture and transfer of the embryo in the laboratory. The most important step in the entire IVF program is the implantation of the embryo.

When the number of embryos to be transferred is particularly limited, the selection of the best embryo for success is made according to (structural) criteria. The embryologist evaluates the the development of the embryo and the structure of the cells under a microscope. The embryo with the highest score may not always be genetically healthy.

 

PGD in Recurrent IVF Failures?

Aneuploidy (an abnormal number of chromosomes) is among the most important causes of IVF (in vitro fertilisation) failures. PGD allows the selection of chromosomally healthy embryos and reduces failure rates. The most common cause of various chromosomal disorders in humans is the advanced age of the mother (especially over 35 years of age). Genetic (chromosomal) anomalies in the embryo are not necessarily a result of an anomaly in the mother or father (or their family). The most common cause is defects that occur by chance during the division of reproductive cells.

 

What are the PGT Techniques?

1- POLAR BODY BIOPSY (SAMPLING)

These are by-products formed after the division of female reproductive cells (egg ). They do not have a reproductive function. They can be easily taken without affecting the embryo formation. Despite these advantages, polar body biopsy cannot detect paternal disorders or anomalies that may occur after embryo division.

2- BLASTOMERE BIOPSY

The embryo reaches the stage of 6-8 cells 72 hours after fertilisation. At this stage, one or two of these cells (blastomere) can be taken by the embryologist in order to carry out a genetic diagnosis. While the removal of two cells may affect the condition of the embryo, genetic diagnoses made by taking a single cell may not always be accurate. Genetic diagnosis results are obtained 24-48 hours after blastomere biopsy. This gives us the opportunity to carry out a transfer during the egg collection cycle. In other words, transfer can be made 5 days after egg collection.

3- TROPHECTODERM BIOPSY

Blastocyst (5th day embryo) consists of two different cell types. The first is the inner cell layer, which will form the baby. The second is the trophectoderm, the outer layer of cells that will form the placenta.

Trophoectoderm biopsy has 2 advantages over other biopsy types. First, the cells that will form the baby are not interfered with in any way, and second, because we sample more cells, its accuracy is much higher. In this form of biopsy, 5-8 cells are taken. The only disadvantage is that the sample has to be frozen after it is taken. The transfer can be made in the next cycle. In other words, IVF treatment is completed in the next month.

Two non-invasive PGT techniques are currently in the trial phase. PGT can be applied both to couples using their own eggs and sperm, as well as those in donation treatments. PGD (PGD) can be beneficial in recurrent in vitro fertilisation implantation failures, as well as in recurrent miscarriages (pregnancy losses).