Preimplantion Genetic Screening (PGS) is a test done on the embryo to check for basic genetic abnormalities. There is also PGD: Preimplantation Genetic Diagnosis which is performed when they are looking for a specific genetic disorder (due to family history). Another bonus of PGS testing is they are usually able to tell you the sex of each embryo (if you want to know)
When the embryo has reached blastocyst stage and scores well, the embryologist performs an embryo biopsy removing a few cells from the blastocyst and sends it for testing. There are only a few laboratories in the country that do this testing because it is so specialized. And due to its high specialty, it can be very to VERY expensive.
Our first IVF doctor encouraged us to do PGS testing stating it could lower our risk for miscarriage. Our second clinic, however, encouraged us not to do the testing stating that the chances of bringing a genetically abnormal child to full term is slim (although it does happen). We ultimately opted out since the testing was even more expensive to do than the first clinic (we decided to pay for 2 rounds of egg retrievals instead of one round and PGS).
When choosing PGS or PGD, they have to fertilize the eggs using Intracytoplasmic Sperm Injection (ICSI). This is done by the embryologist using a microscope to visualize the egg and sperm and physically inject one sperm into one egg that is being held in place with a pipette.
I’ve included a video which perfectly illustrates the ICSI process…click here.
Why ICSI with PGS testing? They want to be absolutely sure that the DNA they pull from the blastocyst is 100% from the embryo and not from sperm that could possibly be on the outside of the blastocyst when fertilized in a petri dish. I hope I explained that well enough but if I didn’t, click here for more information.