Parents always say “I want a healthy baby.”
When it comes to the Preimplantation Genetic Diagnosis (PGD) and Preimplantation Genetic Screening (PGS) tests, they’re often misused and misapplied. Time and again, parents are not adequately equipped with the right questions to ask their healthcare practitioners (including fertility and pregnancy observation specialists) to ensure each vital step has been taken to realize their dream of a healthy baby.
Dr. Nataliia Vladykina, Chief of ADONIS’ Assisted Reproduction, is one of the world’s renowned experts on this topic. She joined us for the ADONIS’ Hot Seat Wednesday to share her expertise, address common misconceptions, highlight trends, and answer questions to equip you with the knowledge you need to make the best decisions.
Here are some key takeaways from the May 13 webinar on PGD and PGS testing:
- Terminology and evolution of the testing
Dr. Vladykina shared that the technology of Preimplantation Genetic Diagnostics (PGD)/Preimplantation Genetic Screening (PGS) has drawn a lot of interest and excitement because this testing opened the possibility of selecting the best embryos. Or so it was thought. There are still significant limitations to what the technology can and can’t do, and therefore can’t be seen as an absolute answer to all things. As the technology and methodology rapidly evolve, additional possibilities open up. As of today, it’s vital to understand what’s actually available and to have an understanding of the terms used so you can be equipped to discuss the specifics of your unique situation. Terms: PGD – preimplantation genetic diagnostic. This was the first term used in the industry. The medical community quickly realized that the term “diagnostic” is not quite accurate. PGD is more of a screening. Therefore the next term was born – PGS.PGS – preimplantation genetic screening. It replaced the PGD term and the two are now used interchangeably.PGT – preimplantation genetic testing is really the most modern term, and should be used when you’re talking to doctors or searching for the latest developments. It’s also important to realize that there are three types of PGT: “PGT for Aneuploidies” (PGT-A) – detects chromosomal abnormalities in embryos, “PGT for monogenic/single gene disorders” (PGT-M) — focuses on reducing the risk to have a child with a known inherited disorder caused by monogenic/single-gene disorders, and “PGT for chromosome structural rearrangements” (PGT-SR).
- There are significant limitations of PGT technology as it stands today. The issue with the validity of this testing (namely PGT-A, the most commonly used) is that a random sample of selected cells does not accurately represent all embryo cells. It is a random sample, which may or may not tell doctors an accurate story. The testing is done through an embryo biopsy, which typically includes 5-6 cells. Taking a sample larger than 6 cells could lead to the destruction of the embryo.
- Who should be looking into PGT: Once again, Dr. Vladykina stressed that PGT is not the answer to all things. It should be used in specific cases and your unique situation must be considered.PGT should be considered for:• Women older than 35 years old
• Couples who have had two or more miscarriages
• Couples who already have a child with chromosomal pathologies
• A parent may be a carrier of a balanced chromosomal abnormality
• Couples who have had multiple failed IVFs
The discussion also focused on questions from the audience, including:
• Further clarifications surrounding mosaic embryos (what it is, can it be transferred, what happens if any future abnormalities have been discovered),
• PGT for previously croyopreserved embryos (pros and cons),
• the necessity of PGT prior to embryo transport to the Ukraine,
• whether PGT reading is the same in all countries,
• specifics of amniocentesis, discussions on possible usage of NIPT or Panorama test for Trisomy for surrogate mothers,
• which chromosomes are being tested for PGT-A 5, 9, 24,
• and more.
ADONIS’ Wednesday Hot Seat
May 13: Common Misconceptions about PGD/PGS
Dr. Nataliia Vladykina, ADONIS’ Chief Reproduction Department
If you did not get the chance to attend, here is the session archive.