Comprehensive chromosome screening is the most effective method of choosing a healthy embryo. Comprehensive Chromosome Screening is a method of screening used to scan all the chromosomes in the embryo cell using microarray technology for couples who plan to have Preimplantation Genetic Diagnosis (PGD). In comparison to the technique called FISH, which is commonly used in routine aneuploidy screening, where a limited number of chromosome deficiencies can be determined, Comprehensive Chromosome Screening enables all chromosomes to be examined for numeral or structural deficiencies, and the embryos with a chromosome deficiency can be omitted from the treatment when conducting the embryo transfer.
The comprehensive chromosome analysis is a method used in IVF before the embryos are transferred into the womb to examine all chromosomes (24 different chromosomes) individually. As the whole chromosome map can be seen in the embryos examined with this method, all the chromosome deficiencies can be detected and unhealthy embryos are therefore not transferred.
The Advantages of The Comprehensive Chromosome Screening in Comparison to Aneuploidy Screening with the Classical PGD Method
The embryos are developed up to the blastocyst phase (5th or 6th day of the embryo development) and multiple cell samples are taken:
It can be determined which embryo has the highest implantation potential.
The level of mozaisism in the developed blastocyst can be seen. Due to the sample cells being obtained from the trophectoderm (which forms the placenta) layer of the 5- or 6-day-old embryo, the cells belonging to the foetus (the baby which is going to be born) are not harmed or its volume is not reduced by the biopsy.
It is not an easy procedure to examine all the chromosomes of a developing embryo and a specific amount of time is required for this procedure. If a biopsy has been conducted on the 5th morning, then the genetic analysis results will be available on the 6th day and a fresh embryo transfer can be conducted.