Pre-implantation genetic screening (PGS) is a genetic test that also may be performed during IVF treatment. This test screens chromosomes for possible forms of aneuploidy prior to implantation. Aneuploidy can result in disorders such as Down’s Syndrome, referred to as trisomy 21. The rate of chromosome abnormalities is significantly higher in women 35 years of age and older.
Chromosome abnormalities are one of the main factors that cause recurrent miscarriages. These abnormalities are also linked to birth defects in babies. Couples may consider PGS test in the following circumstances:
In PGS testing, a genetic biopsy of several cells is obtained from a blastocyst-stage embryo after 5-6 days of development. The biopsied samples are sent to a reference laboratory to evaluate all 24 pairs of chromosomes: 22 non-sex chromosomes and 2 sex chromosomes (X & Y). PGS testing identifies chromosomally normal embryos, thereby increasing the chance of conceiving a healthy baby.
PGS is more affordable than PGD, and is often used to maintain family balance by overseas patients. PGS can screen for the following chromosomal disorders: