Preimplantation Genetic Testing (PGT-A)
During the laboratory process of Preimplantation Genetic Testing- A for aneuploidy or PGT-A (previously known as Preimplantation Genetic Screening or PGS) embryos at the blastocyst stage created during an IVF cycle undergo a cell biopsy on day 5 or 6 of development and cells are sent to a genetics laboratory to determine the chromosomal status of each embryo by screening all 23 chromosome pairs. Embryos are screened for aneuploidy (missing or additional numbers of chromosomes), which is a leading cause of miscarriage and implantation failure (failure of the embryo to implant into the uterus).
Assisted Hatching is a laboratory procedure performed on the outer shell of the embryos on day 3 of in vitro development for those embryos that will eventually undergo PGT-A as blastocysts on Days 5 and 6.
During the Assisted Hatching procedure, a small opening is made in the outer shell of the embryo, called the zona pellucida, in order to assist the embryo in breaking out of this shell to facilitate the biopsy procedure performed for PGT-A.
Screening for Chromosome Abnormalities
All 23 pairs of chromosomes, including the sex chromosomes, will be screened for abnormalities to help increase the chances for couples to have a chromosomally healthy child. It can tell us if the correct number of chromosomes are present or if an abnormal number of chromosomes are present. In addition, Fertility Specialists of Texas now offers chromosome screening for couples who have cryopreserved embryos from past cycles that were not previously tested. Through this process, available at only a few IVF programs in the country, embryos that have been cryopreserved can be thawed and tested to determine if they are Euploid (genetically healthy) male or female embryos, before being transferred back into the woman.
The laboratory we use for PGT-A utilizes the most sophisticated and scientifically validated Next Generation Sequencing technology for determining the chromosome complement in a single cell.