Preimplantation Genetic Screening (PGS)
Pre-implantation genetic screening (PGS) also known as pre-implantation genetic testing (PGT) is a PGD technique that identifies embryos at overall risk instead of analyzing them for a specific genetic disorder. During PGS testing, total number of chromosomes are evaluated from a small number of cells of an embryo produced as a result of an IVF procedure. These cells are collected from the trophectoderm layer of the embryo during the blastocyst stage of the process. PGS testing is done in order to improve a patient’s chances of pregnancy while reducing chances of miscarriage.
Scientifically, an embryo with normal number of chromosomes (46) – 23 from each parent – has a better chance of implanting and resulting in a healthy pregnancy. Embryos with missing or extra chromosomes (known as aneuploid) generally result in either miscarriage or a baby with chromosomal abnormality such as Down syndrome. In the past, the embryo selection was primarily based on the “look” of the embryo or morphology. However, even the best looking embryos can be genetically abnormal. The chart below shows the correlation between aneuploidy and implantation. PGS helps identify healthy embryos which can then be implanted into the patient. For more please watch: Improving IVF success with PGS
Who can benefit from PGS?
- IVF patients over the age of 35
- Patients with repetitive unsuccessful IVF cycles (2 or more)
- Women with diminished ovarian reserve, regardless of age
- Individuals who have experienced multiple miscarriages
- Couples interested in Gender selection
Why consider VCRM for PGS?
- High Success Rates: VCRM has one of the highest IVF success rates on the US east coast
- Personalized Treatment: All your appointments will be conducted by Dr. Sharara unlike large practices where you are treated by a variety of physicians
- Friendly & Caring Staff: Our staff is regularly praised by old & new patients for being the best in the industry and for helping make a tough process much easier
The following steps are taken during the PGS process.
VCRM has been on the cutting edge of PGS and our newest addition will result in an even lower chance of false positive results. We have recently started offering the newest technology in PGS screening, namely next-generation sequencing (known as “next-Gen”), through Genesis Genetics. This technique requires more time to get the results back and therefore we need to freeze the embryos for a later transfer in an FET cycle. However for the vast majority of our patients, we offer fresh day 6 transfer after PGS with rapid turnaround using a-CGH technology, rather than having to freeze the embryos for a later transfer. We perform the embryo biopsy on day 5, followed by transfer on the morning of day 6 as soon as we have the results of the genetic testing (usually by 9 am on day 6).
Our ongoing pregnancy rate for fresh day 6 transfers (for women using their own eggs) are currently 63% (January-December 2015) when one euploid (genetically normal) embryo is available for transfer. It is important to note the some women will not have a blastocyst by day 5 (especially older women and those with diminished ovarian reserve): the cancellation rate increases from 4.7% for women < 35 to 21% in women 41-43, and some will not have any normal embryo to transfer (this increases from 9.5% in women < 35 to 21% in women 41-43). (Please note that a significant number of our patients have failed multiple cycles at other programs, so the above rates may not apply to those who are doing IVF/PGS for the first time).
With the advent of next generation sequencing (NGS), which is the latest and most accurate technology to test for aneuploidies, we now have to freeze the embryos (the results take about 5-7 days) for a later transfer in a programmed frozen cycle. This allows the best chances at conception with excellent success rates.Please call our office at 703-437-7722 for further details.
Please watch this excellent short video explaining PGS