PGS - How This Acronym Can Provide Insight Into Your Embryos

May 08, 2018

If you’ve never heard of PGS, it stands for Preimplantation Genetic Screening and it’s a procedure used to determine the chromosomal status of an embryo created through In Vitro Fertilization (IVF). If you have been going through IVF or even if you haven’t been going through treatment but have suffered several miscarriages, you may want to learn more about Preimplantation Genetic Screening (PGS). As a patient, you are your best advocate so the more you know, the more you can speak to your doctor and see if this is something worth exploring.

A Quick DNA Lesson

First, some math. 46 chromosomes (2 copies of each) is the total number of chromosomes in a human cell. This translates to 23 pairs per cell. If someone has an extra chromosome in one of those pairs (meaning they have 47 in total), this extra chromosome is called a trisomy. One example of a chromosomal abnormality that can be detected by PGS is an extra copy of chromosome 21, which causes a trisomy 21 or Downs Syndrome. Chromosomal abnormalities are primarily responsible for failure of implantation of IVF embryos and put the patient at higher risk for miscarriage.

PGD PGS

What is PGS and How is it Different from PGD?

Preimplantation Genetic Screening (PGS) is a test used to screen an embryo for a normal chromosome number. Preimplantation Genetic Diagnosis (PGD) is a test used when screening an embryo for a specific gene disorder, such as sickle cell anemia, cystic fibrosis or Tay-Sachs. In both cases, these tests can only be performed on embryos created through IVF.

How Does it Work?

Both PGS and PGD are performed prior to an embryo transfer to help identify specific genetic conditions. A few cells are removed from the embryo (specifically the portion of the embryo destined to be the placenta) and are tested for chromosomal abnormalities or certain genetic mutations. The embryo is frozen right after it is biopsied while you and your doctor wait for the results of the testing. Healthy embryos are then subsequently thawed and transferred to the woman (or gestational carrier) in the hopes that it will implant and result in a healthy pregnancy.

Benefits of PGS in General

Chromosomally Normal babyGS screens for overall genetic normality, this means that the embryos transferred typically have a higher implantation rate and a lower chance of miscarriage.

Some who may want to consider using PGS are those who are of advanced maternal age (as the older you get, the higher the risk is for having more genetic abnormalities), those who have a history of multiple failed IVF cycles or those who have recurrent unexplained miscarriages.  However, PGS can be effective in all age groups and allows for a quicker interval to pregnancy and decreased rates of miscarriages in general.

Questions You May Want to Ask as Kofinas Fertility About PGS:

  • Does PGS harm the embryo in any way? 
  • Who do you recommend should consider using PGS?
  • How much does PGS cost?
  • If I’ve had recurrent miscarriages, do you think PGS will help?
  • What are the success rates of single embryo transfer following PGS versus no PGS?

Although no one relishes the idea of adding more steps to an already long family building journey, if screening up front can prevent considerable complications down the road and increase your odds of carrying a chromosomally healthy baby to term, it sincerely is worth it.

Please make an appointment with us so we can discuss it further!

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