What Is the Difference Between PGS and PGT-A?
By Dr. Paul Gindoff, Chelsea Fertility NYC Founder
As reproductive technologies advance, there can be updates to preferred procedures and even terminologies. An example of such a change is the simple nomenclature transition from PGS to PGT-A. There is no procedural difference / change between the two, but the terminology shift will become more prevalent in the fertility community in the next few months / years. In order to assist patients with their understanding of the two, we’ve provided an explanation by Dr. Paul Gindoff below.
Of course, we always encourage patients with questions about fertility treatment to contact our team directly so we can assist. So if there’s anything you’re unsure of or would like clarification on, please contact our team today.
PGS vs. PGT-A: An Explanation
- PGT-A, formerly known as PGS, is preimplantation genetic testing for an aneuploidy. This procedure involves the culturing of embryos to the blastocyst stage and a biopsy to allow for the testing of a sample of cells from the embryo.
- This process is completed without damaging the embryo, so it can be utilized for transfer back to effect a pregnancy once the results are known.
- PGT-A is utilized to evaluate the chromosomal genetic integrity of embryos as far as normal or abnormal numbers of chromosomes for each cell. In other words, it checks the karyotype, which is either 45XY or 46XX.
- Only normal embryos have normal karyotypes and therefore would lead to a healthy pregnancy and delivery. The corollary is that abnormal PGT-A embryos will not implant or will lead to a miscarriage. Rarely would an abnormal embryo like a Down syndrome 47XX+21 or 47XY+21 result in a live birth.
- PGT-A doesn’t test for genetic diseases such as in-born errors of metabolism, sickle cell disease, muscular dystrophy, Huntington’s chorea, or polygenic diseases like diabetes or heart disease.
- If there is a family history of these metabolic or genetic diseases, there is a similar test called PGT-M to allow biopsy of embryos and testing for the specific abnormal gene causing the disease in question.
The physicians of Chelsea Fertility NYC have long-term experience in PGT-A, as they are some of the first in the field to utilize this technology and are also published in this area. If you are interested in learning more about preimplantation genetic testing at our practice, please contact Chelsea Fertility NYC today.