PGT-A, formerly known as PGS, is a preimplantation genetic test that can identify embryos that have the normal number of chromosomes as well as those that have an abnormal number of chromosomes. Normal human embryos have 23 pairs of chromosomes. One copy of each chromosome pair is inherited from the mother and the other from the father, resulting in a total of 46 chromosomes. Abnormalities that occur during the fertilization of the sperm and egg or during the early development of the embryo may cause the embryo to have less than or more than 46 chromosomes. Embryos with a normal number of chromosomes are considered “euploid” and those with an abnormal number of chromosomes are considered “aneuploid”. Aneuploidy embryos can result in failed implantation, miscarriage, or the birth of a child with health problems. The PGT-A test allows us to identify euploid and aneuploid embryos by examining the chromosome numbers of embryos before embryo transfer in IVF. PGT-A test is used to increase the chance of pregnancy, prevent miscarriage, and have a healthy child by selecting healthy embryos before embryo transfer.
Who can benefit from PGT-A?
- Women over the age of 36
- Those with severe male factor infertility
- Those with recurrent pregnancy loss
- Those with recurrent IVF failures
- Translocation carriers
- Couples with a family history of chromosome problems
In our clinic PGT-A can be performed using the following techniques:
NGS (Next-generation sequencing)
NGS is testing all 23 pairs of chromosomes. In the NGS technique, embryo biopsy is performed on Day 5 (blastocyst stage) of embryo development. A few cells are removed from the placenta of each embryo and these cells are sent to the laboratory for testing. Embryos are frozen and stored until the result of the test. The test results in 3 weeks. According to the test result, aneuploid and mosaic embryos are destroyed, euploid embryo(s) are stored in the laboratory to be transferred to the uterus.
FISH (Fluorescence in situ hybridization)
FISH is testing the 13, 16, 18, 21, 22, X, and Y chromosomes. In the FISH technique, embryo biopsy is performed on Day 3 (cleavage stage) of embryo development. A few cells are removed from the placenta of each embryo and these cells are sent to the laboratory for testing. The test results in 1-2 days. Fresh embryo transfer is performed on Day 5 (blastocyst stage) of embryo development.
