Preimplantation Genetic Testing (PGD or PGS)
Preimplantation genetic testing involves highly sophisticated testing cells of an embryo created through in vitro fertilization (IVF) to determine if there they carry an abnormality or mutation that could affect the health of the baby now or in future generations.
The results are used to identify the healthiest embryo(s) to implant or preserve and/or to rule out genetic diseases that are either certain or possible to occur.
Preimplantation genetic diagnosis (PGD) is something to consider if you or your partner know you have any of the following:
- A genetic disease
- A chromosome abnormality
- A child who has a genetic disease
- Knowledge you are a carrier for a genetic disease
Preimplantation genetic screening (PGS) is much like PGD, except that PGS is used when no known concerns are present to identify embryos at risk for chromosomal abnormalities.
PGS is something to consider if:
- You are over the age of 35
- You have had two or more miscarriages
- You have had more than two unsuccessful cycles of IVF
- You have unexplained infertility
Miscarriages or pregnancies that are lost early on are often due to chromosomal abnormalities. These abnormalities often occur because the quality of the eggs are beyond their prime and have incurred changes in the chromosome pair such that they are not the normal healthy matched they should be for healthy children.
PGS screens for chromosome abnormalities such as translocation, broken chromosomes, an abnormal number of chromosomes, and other discrepancies.
The PGD and PGS Process
Preimplantation Genetic Diagnosis (PGD) occurs as part of the IVF process after Preimplantation Genetic Screening (PGS).
- The eggs are fertilized in the laboratory after a retrieval like in every IVF cycle
- The embryos that seem to be developing the best are selected for screening after 3 or 5 days
- One or two cells are extracted from these embryos and screened through highly sophisticated equipment to identify if there are any abnormalities that could cause genetic diseases or complications going forward
- After reviewing the results, the healthiest embryo will be transferred to the woman’s uterus
- Any extra embryos of high quality may then be frozen for use in the future.
Once the screening has taken place, only the embryos that are healthy and free of abnormalities will be either placed in the uterus to continue to grow into a baby or stored for future use.