Comprehensive Chromosome Screening is a technique used in parallel with IVF treatment to select embryos with the right number of chromosomes. After in vitro fertilization, a small number of cells from each embryo are biopsied and sent to the genetics lab for testing.
The purpose of chromosome screening is to analyze, select and transfer only embryos that have the normal number of chromosomes. It is known that aneuploidy – any embryo with too many or too few chromosomes – is the cause of over 60% of miscarriages and a most likely reason for failure to achieve pregnancy during an IVF cycle.
Preimplantation Genetic Screening (PGS), also known as aneuploidy screening, using Next Generation Sequencing (NGS) is widely used to select competent embryos, free of chromosome abnormalities, for embryo transfer. This embryo selection improves clinical outcomes by achieving a higher implantation rate and a reduction in miscarriage rates.
Who is suitable for Comprehensive Chromosome Screening?
- Women 35 years of age or older
- Women with a history of repeated miscarriage
- Women with a previous pregnancy involving a chromosome abnormality
- Woman who have had multiple failed IVF cycles or implantation failure
What methods are available?
- FISH (Fluorescent in situ hybridization) requires removal a single cell on Day 3 or several cells on day 5 or 6 of embryo development. The FISH test is done using fluorescent probes that bind to certain specific chromosomes. The 5 probe FISH method screens for the five important chromosome which includes X,Y,13,18 and 21.
- Next-Generation Sequencing (NGS) is the latest technology in genetic testing all 23 pairs chromosomes and sex chromosome at a more comprehensive level and with high resolution. NGS provides the ability to screen embryos from chromosomes errors such as Down syndrome and other similar aneuploidy conditions.