Preimplantation Genetic Screening & Diagnosis Testing (PGS & PGD)
PGS and PGD are terms that refer to the testing of an embryo for specific genetic diseases that can be transmitted from the parents.
PGS refers to the screening for an abnormal number of chromosomes (aneuploidy). This approach screens all 23 pairs of autosomal chromosomes as well as the 2 sex chromosomes. PGS is recommended more often by fertility specialists when discussing infertility due to advancing maternal age, repeated IVF failures, recurring pregnancy losses, or those with a history of genetically abnormal pregnancies.
PGD is the diagnosis of a single gene defect in the embryo for couples that are known to have a single gene mutation. The purpose of this testing is to ensure that offspring won’t have the disease. Most commonly, this group of patients has a 25% – 50% risk of transmitting a significant medical illness to their child.
Some of the disorders diagnosed using PGS: Down’s Syndrome (Trisomy 21), Trisomy 18, Polyploidies, Monosomy 16
Some of the single gene disorders diagnosed using PGD:
Sickle Cell Anemia
When and how does PGS/PGD happen?
After your eggs have been fertilized in-vitro during an IVF cycle, and using microscopic guidance, the Embryologist removes cells from the trophectoderm of a blastocyst (5-6 day embryo) and tests for abnormalities. After biopsy and testing of the embryo’s genetic material, embryos will be selected based on their absence of irregularities for tranfer and/or freezing.
PGS/PGD can increase the chances of pregnancy, minimize the risk of pregnancy loss, and afford the parents the chance to avoid undesired genetic traits.
Based on your medical history, your fertility specialist may discuss this specialized testing with you at the time you are considering undergoing IVF.
There is an additional fee for this specialized testing that is not included in the IVF fees so please ask your nurse for more details.