Patient Portal: PGS
Pre-implantation Genetic Screening (PGS) is a highly specialised technology that involves the biopsy of embryos to assess whether or not they carry the correct number of chromosomes. Waterstone Clinic is the first Irish clinic to have a successful embryo biopsy service. Only an embryo with the correct number of chromosomes (euploid embryo) will be selected for transfer into the woman’s uterus. By avoiding the transfer of aneuploid embryos (embryos with extra or missing chromosomes) PGS significantly increases the chance of having a successful pregnancy after embryo transfer. It also decreases the chance of miscarriage and, considerably reduces the chance of having a baby with a chromosome anomaly.
- Couples who have experienced recurrent and unexplained miscarriage
- Couples who have had repeated unsuccessful IVF cycles (recurrent implantation failure) – where good quality embryos have been transferred into the womb yet pregnancy has not resulted.
- Advanced female age (it is well-recognised that the risk of aneuploidy increases with increasing maternal age)
With PGS, embryos are generated using a form of IVF treatment known as intracytoplasmic sperm injection (ICSI). PGD involves one extra step within an IVF cycle (click here for information on what an IVF cycle involves).
- Following egg collection, the eggs are fertilized with prepared sperm to create embryos.
- These embryos are cultured and monitored for development.
- After five days, embryos which appear to be developing normally are suitable for PGS embryo biopsy and genetic analysis.
- The genetic analysis of each removed cell takes place at a specialist genetic centre in the UK
- The embryo(s) that are diagnosed as euploid (having the normal complement of chromosomes) are then selected for transfer into the womb or cryopreserved for use in a future frozen embryo transfer cycle
Theoretically, the transfer of a genetically normal embryo should increase the chance of a successful pregnancy and decrease the chance of miscarriage. However, PGS is not recommended for every couple doing IVF treatment as the addition of PGS has not been shown to improve overall livebirth rates in the general IVF population. There is a risk of a false positive result (an embryo is deemed abnormal and discarded but is in fact chromosomally normal) and also a risk of a false negative rate (an embryo is deemed normal and transferred but is in fact chromosomally abnormal). For couples interested in PGS there is a detailed information and consent process.