PGS
Preimplantation genetic screening (PGS) is advised in certain groups of patients undergoing IVF who have an increased chance of producing chromosomally abnormal (aneuploid) embryos. These patients include older women (aged 38 years or older), women that have had repeated failed attempts at IVF and women who suffer from recurrent miscarriage.
The technique involves analysing specific chromosomes from a single cell of an embryo that has been produced through IVF. Removing a single cell from the embryo, called embryo biopsy, is done when the embryo is 3 days old. Only embryos that are found to be chromosomally normal are transferred into the uterus and this is done on day 5 when they have become blastocysts. PGS only increases the chances of successful outcome in patients that respond well enough to the IVF stimulation drugs to produce a good number of embryos to biopsy. There is a risk that no embryos will be found to be normal or that the embryos fail to grow to the blastocyst stage. It is for this reason we do not usually suggest PGS in the first cycle of IVF treatment.
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