Preimplantation Genetic Testing (PGT-A)
Author : Professor Maged Adel Aziz
• Updated at: Jun 09, 2024 •
Preimplantation genetic testing for Aneuploidies (PGT-A) is a test to detect chromosomal abnormalities an is one of the most important tests that is carried out in IVF or ICSI before the embryos are returned to the mother's womb. When an egg is fertilized with a sperm artificially, the embryos are placed in smart incubators to grow and divide cells naturally. After five days of follow-up and monitoring growth and division, a biopsy is taken to check the number of chromosomes of each embryos.
This examination helps in discovering embryos that are not genetically sound. They may contain fewer or more chromosomes. Genetically healthy embryos are implanted and the unhealthy ones are disposed of.
Preimplantation Genetic Testing for Aneuploidies (PGT-A)
PGT-A Is a genetic test that is performed before transferring back the embryos. It identifies any chromosomal anomalies by NSG technology which we provide in Bedaya hospitals’ Laboratory.
This technology allows doctors to analyze the 24 pairs of chromosomes and detect disorders before transferring them to guarantee higher success rates of IVF or ICSI
PGT-A does not test for the following:
- Genetic syndromes.
- Birth defects.
- Single gene disorders.
- Multifactorial conditions.
- Physical and mental traits.
The importance of PGT-A
Pre-implantation genetic testing to detect chromosomal anomalies makes it possible for doctors to choose the best embryos for uterine transfer thus avoiding miscarriages or unhealthy pregnancies. Statistics show that women aged 38 to 40 who underwent an IVF process had a chance of chromosomal abnormalities in fetuses reaching up to 64%. To avoid implanting an embryo that has morphological or numerical abnormalities in its chromosomes this examination is done before embryo transfer to the uterus.
Before undergoing any procedure, you have the right to inquire your doctor about the risks and benefits of the procedure. this will help you take better decisions according to your situation.
The advantages of PGT-A
- Being able to choose a healthy embryo for transfer will increase the success rates of pregnancy.
- Reducing the risk of miscarriages. 20%-25% of clinical pregnancies may end up miscarrying.
PGT-A allows doctors to choose an embryo with a normal 46 chromosome pattern which decreases the miscarriage rates. - It saves time and money, with the success of an IVF/ICSI procedure resulting in a healthy pregnancy a couple will save on other possibly failing procedure attempts.
- Avoiding the risk of multiple pregnancies. Implanting one tested healthy embryo is much better than implanting multiple untested embryos.
- Increased chances of delivering a healthy child.
PGT-A process
- On day 3 of the ICSI \ IVF, the embryologist will take a biopsy of one cell for investigations. Occcasionally the genetic biopsy is taken on day 5 when the embryo has entered the blastocyst phase.
- The samples are sent to the genetic reference lab.
- Chromosome analysis is done by embryologists (PGT-A test).
- The doctors and the embryologists come up with genetic reports that state if there are any present chromosomal anomalies.
- Elimination of the abnormal embryos is done after the parents sign a consent form. The healthy embryos are transferred to the uterus.
