Genetic Testing of Embryos
Traditionally, local couples wishing to have genetic testing of their embryos have had to travel to England but this will soon be available at GCRM-BELFAST.
Pre-implantation genetic diagnosis (PGD)
This is a very specific technique which can be used where a serious genetic disease which could be passed to offspring is to be avoided.
By creating embryos in a similar way to ICSI treatment, a single cell or group of cells can be removed from an embryo and the genetic material contained in the cells’ chromosomes can be analysed to see if it carries that disease or not. Very careful preparation is required before undertaking this form of treatment and may require blood sampling from family members. Our specialist team will guide you through the steps required.
Pre-implantation genetic screening (PGS)
Analyses the genetic constitution of an egg or embryo to determine whether the genetic material is normal or abnormal. It does this by using the technique called array CGH which compares the embryo DNA with normal DNA, and allows us to select only genetically normal embryo(s) for transfer.
There are 2 main approaches to the testing. The first method involves removing cells from an advanced embryo (blastocyst), and testing the DNA of these cells. The other method involves testing the polar body (a waste product) of the egg which reflects the genetic status of the egg.
In theory, by excluding abnormal eggs and embryos the procedure should increase the chances of a successful pregnancy. However, it also increases the chances of having no embryos to transfer in that cycle if all the eggs/embryos are chromosomally abnormal.
Historically, evidence supporting the benefits of PGS was not strong. This newer approach (array CGH, see attachment) should provide advantages in specific patient groups and the latest evidence from several clinics has been very encouraging. For further information please click here.