Preimplantation Genetic Testing (PGT-A), also often known as Aneuploidy Screening, is a procedure in which the embryos created through Intracytoplasmic Sperm Injection (ICSI) are examined for chromosomal abnormalities. Pregnancies where embryos show chromosomal abnormalities often end in miscarriages or result in conditions such as Down Syndrome.
PGT-A is a genetic test where cells are examined to check for abnormal chromosomes. Abnormal chromosomes occur when the cells of eggs, sperm, and embryos divide, leading up to too many, too few chromosomes, missing or added pieces of chromosomes in the embryo.
Who will benefit from PGT-A?
Preimplantation Genetic Testing (PGT-A) is recommended for those who have had recurrent implantation failure. It means the patient has undergone several IVF cycles that have failed, despite having good quality embryos. Women who have had recurrent miscarriages also are suggested Preimplantation Genetic Testing.
PGT-A is also recommended when a woman opting for pregnancy is over 40 years. A fertility specialist may also recommend PGT-A if there has been a history of some chromosomal abnormalities.
Here are some indications for PGT-A
Women with recurrent pregnancy loss (miscarriages)
Women with recurrent IVF failures
Women with advanced maternal age
Identify chromosomal abnormalities which could be contributing to the problem.
How is PGT-A performed?
The first step involves extraction of eggs with the help of ovarian stimulation using medications. Post egg retrieval, the sperm is injected into the egg using ICSI and then the embryos are grown in the lab for up to 5 days. A biopsy of a few cells in the trophectoderm layer, i.e. the outer layer of an embryo, is taken and sent for genetic examination. The cells are checked for any chromosomal abnormalities in the embryo.
As it can take up to a week for the PGT-A test results to be available, all the biopsied embryos are usually frozen. Once the results are available, chromosomally normal embryos are implanted in a frozen embryo transfer process, and the chromosomally abnormal embryos are discarded.
Risks involved in PGT-A
PGT-A is a developing procedure and with new technology coming into the field, diagnosing abnormalities is better. However, it’s not entirely risk-free. Research has shown that the embryo’s cells are often not chromosomally identical (called mosaicism), and PGT-A bases its findings on a small set of cells.
Despite a limited risk to the embryo that is being tested, it is a procedure to opt for in certain cases such as when the age of the women are over 40, there is a history of some sort of genetic abnormality and where there have been a few failed IVFs and miscarriages.
PGT-A at Mother To Be
We have been offering this advanced technology for indicated couples since 2013. The expertise of the clinical and embryology team matters most here, and we are in a privileged position to offer this technology.
Watch Dr Vyjayanthi explain the process of Preimplantation Genetic Testing (PGT-A).
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