Preimplantation genetic screening for PGS
Studies have shown that embryos produced in test tubes have a high rate of chromosome aneuploidy. Most types of aneuploidy are incompatible with life, and aneuploid non-sex chromosomes cause some of the most common syndromes, including Down's syndrome, Edwards syndrome, and Pato syndrome. Aneuploidy is usually not hereditary and can be produced by any chromosome. In addition, embryos from late reproductive age mothers have significant events with chromosomal mutations.
Thus, such embryos reduce the potential to achieve viable pregnancy, leading to implant failure and spontaneous abortion, and thus a relatively low success rate is observed during IVF treatment.
50% of spontaneous abortions are caused by chromosome aneuploidy including embryo birth defects. The risk of children with abnormal chromosomes has been increasingly observed at maternal age. For couples with an increased risk of aneuploid embryos, the PGS test should be considered.
These groups include:
Women over 35 years old
Couples who have experienced several unexplained spontaneous abortions
With several IVF cycles of unfinished pregnancy
Male with low sperm concentration
Couple with chromosomal abnormalities in previous pregnancy
PGS is used to screen for normal chromosomal embryos, thereby enabling these couples to significantly reduce the risk of miscarriage and increase the success rate of pregnancy.
The use of preimplantation genetic screening for selective normal embryo implantation helps:
Improve transplant success rate: abnormal or aneuploid embryos will not be implanted in the female uterus. Therefore, the use of PGS to diagnose normal chromosomal embryos prior to embryo transfer can increase the success rate of transplantation.
Reducing spontaneous abortion: Several studies have found that abortion is often caused by a new number of chromosomes or aneuploidy. Since PGS can assess numerical and aberrational changes on chromosomes as well as large imbalances in chromosomes, abnormal embryos are not transferred. PGS reduces the risk of miscarriage, especially for high-risk groups.
Increasing the rate of continued pregnancy allows single embryo transfer, reducing the number of high-risk multiple pregnancies
Preimplantation genetic screening (PGS) plays an important role in assisted reproductive technology by improving the results of IVF by detecting chromosomal abnormalities in the embryo. In addition to common aneuploidy, other genetic structures of chromosomal abnormalities, chromosomal rearrangements, including translocations, inversions and repeats/deletions, can be screened by PGS. In addition, some chromosomal abnormalities such as aneuploidy can also use PGD.
In addition, some chromosomal abnormalities such as aneuploidy is possible for PGD
There are new molecular genetics techniques that have recently replaced the FISH method for aneuploidy screening including array comparative genomic hybridization (aCGH), single nucleotide polymorphism (SNP) arrays, quantitative PCR (qPCR).
The latest molecular genetics technology replaces fluorescence in situ hybridization (FISH) for aneuploidy screening, including microarray comparative genomic hybridization (aCGH), single nucleotide polymorphism (SNP) arrays, and quantitative PCR ( qPCR).