Life Clinic  > Fertility treatments  > Preimplantation Genetic Diagnosis (PGD)

Preimplantation Genetic Diagnosis (PGD)

This is an advanced technique first developed in the early 1990s. It is used to detect genetic disease and chromosomal disorders in embryos created through in vitro fertilisation (IVF). Up to 60% of early miscarriages are due to chromosomal adbnormalities.

Currently there are various types of PGD available depending on the needs of each couple. PGD essentially involves the collection and genetic analysis of early-stage embryos (approximately three-days old). Healthy embryos with normal genetic and chromosomal structure are selected and transferred into the uterus for implantation. PGD does not involve manipulation of the genetic material in the embryos but rather it allows selection between them.

PGD is able to detect most known genetic mutations. It is widely used by couples who are at risk of having a child with a serious genetic disorder, including chromosomal diseases such as Down's Syndrome and other genetic disorders such as cystic fibrosis, sickle cell disease, Tay-Sachs disease, Huntington's Chorea and spinal muscular atrophy.

Preimplantation Genetic Screening (PGS)

This is variant of PGD which is also provided at Life Clinic. It is used specifically to detect aneuploidy, a chromosomal disorder. Perhaps the most known form of this is Down's Syndrome where an extra chromosome is present.

Flourescent in-situ hybridisation (FISH) analysis

This is a relatively recent technology which is used in the laboratory to determine whether the correct number of certain chromosomes is present in the egg or embryo. The chromosomes most commonly associated with abnormalities during pregnancy are analysed. These are chromosomes 13, 16, 18 and 22. Flourescent signals bind to these chromosomes enabling their number to be established. FISH has a published accuracy rate of 95%. However, it is important to realise that in some cases this analysis may reveal that no normal embryos are available for transfer or that the chances of being able to store excess embryos from an egg collection may be reduced.

the risks of chromosomal disorders such as Down syndrome increase with maternal age.