Preimplantation genetic diagnosis (PGD-PGS)

PGD involves a genetic testing of embryos followed by the selective transfer of genetically abnormal embryos.

The pre-implantation diagnosis is recommended for couples who have a high risk of transmission of specific gene mutations (by the method of PCR) or numerical / structural chromosomal abnormalities (with the method FISH) to their children.
Some common genetic diseases that can be prevented through PGD is thalassemia, cystic fibrosis, Down syndrome, etc.

The pre-implantation diagnosis has also expanded an embryos’ control to improve pregnancy rates in specific groups of patient (PGS). The indications for pre-implantation embryos check include patients of advanced reproductive age, repeated IVF failures, recurrent miscarriages, and severe male factor infertility.
The development of the pre-implantation diagnosis technique results in the comparative genomic hybridization to microarrays nucleotides (array CGH). This method allows to control the entire genome and provides useful information on the frequency and type of abnormalities in embryos.

In the process of pre-implantation diagnosis, an embryologist performs a biopsy by removing one or two cells from each embryo with a help of a special micropipette, usually done on the third day after an egg collection. Then, the genetic material of cells is analyzed in order to detect genetic abnormalities. Abnormal embryos are not implanted. Only selected healthy embryos are transferred to the uterus and usually on the fifth day after an egg collection.