It can identify embryos with abnormal chromosome numbers, but it cannot guarantee successful implantation. It also cannot rule out single-gene disorders (in which case PGT-M is required).

PGT-A stands for Preimplantation Genetic Testing for Aneuploidy. In clinical practice, it was often referred to as PGS (Preimplantation Genetic Screening). The technique involves analyzing several cells from the blastocyst stage to determine whether the embryo's chromosomes are normal.

A normal human embryo should contain 46 chromosomes, or 23 pairs of diploid cells. If there is an extra or missing chromosome, it indicates an aneuploidy disorder. Examples include trisomy 21 (Down syndrome), trisomy 16, trisomy 18, and various monosomy disorders. Most of these abnormalities prevent the embryo from developing to full term, making them one of the main causes of failed implantation, early miscarriage, and poor implantation.

Therefore, the key clinical benefit of PGT-A is its ability to identify embryos with abnormal chromosome numbers before transplantation. This reduces the risk of miscarriage due to chromosomal issues and improves the success rate of single-transplantations. This test is particularly useful for older individuals, those with recurrent miscarriages, those who have experienced multiple failed implantations, and those who have previously had aneuploidy embryos detected.

However, it has limitations:
First, it cannot guarantee successful implantation. Embryos with normal chromosomes may still fail due to factors such as endometrial receptivity, immune factors, or embryonic development potential.
Second, it cannot rule out single-gene disorders. Conditions like thalassemia and spinal muscular atrophy require PGT-M, and the testing targets are completely different.
Third, there is a risk of misjudgment due to the small number of cells sampled from the blastocyst. The results are "highly likely" rather than absolute.
Fourth, sufficient numbers of blastocysts are required. If there are only 1-2 blastocysts, none may be suitable for transplantation. This risk must be carefully considered before proceeding with the procedure.

Whether to undergo PGT-A should be determined based on factors such as age, history of miscarriages, number of blastocysts available, and financial resources. It should not be viewed as a "guarantee" of higher success rates.