In a standard IVF treatment, every time a cycle produces more than one embryo, a choice must be made about which embryo will be transferred. That choice is determined by the development and appearance of the embryos.
However, recent scientific advances mean PGT gives us another decision-making factor - the genetic health of the embryo.
Pre-implantation genetic diagnosis (PGD) refers to genetic profiling of embryos created through IVF prior to the transfer into the patient’s uterus. During PGD the embryos are screened for a number of specific genetic disorders, so as to exclude the possibility of selected embryos having these particular abnormalities.
PGD enables patients with a chronic disease in their family history to avoid passing it on to their children. A specialist may recommend PGD if patients have a family history of severe genetic diseases or previous miscarriages due to genetic disorders.
The term preimplantation genetic screening (PGS) is used to denote procedures that do not look for a specific disease but use PGD techniques to identify embryos at risk. PGS involves checking the embryos chromosomes for common abnormalities. Chromosomal abnormalities are a major cause of miscarriages and the failure of embryos to implant. They can also cause such serious medical conditions as Down’s syndrome.
PGS is normally recommended for: