Just in case you didn’t get enough technical details in my last post about PGD, PGS, CCS, and preimplantation genetic testing, I wanted to highlight this very technical and in depth article from the Journal of Assisted Reproduction and Genetics. It talks about the old FISH method of PGD (testing only a limited number of chromosomes) and compares it to todays technologies for comprehensive chromosome screening (CCS) of the human genome. It addresses the various methods/technologies and limitations of CCS in far more depth and detail – which I, as a technology nerd, find fascinating. So, I’m sharing it with my fellow ART technology geeks.
Here’s the abstract:
“Preimplantation aneuploidy screening of cleavage stage embryos using fluorescence in situ hybridization (FISH) may no longer be considered the standard of care in reproductive medicine. Over the last few years, there has been considerable development of novel technologies for comprehensive chromosome screening (CCS) of the human genome. Among the notable methodologies that have been incorporated are whole genome amplification, metaphase and array based comparative genomic hybridization, single nucleotide polymorphism microarrays, and quantitative real-time PCR. As these methods become more integral to treating patients with infertility, it is critical that clinicians and scientists obtain a better understanding of their capabilities and limitations. This article will focus on reviewing these technologies and the evidence of their validity.”
You can find the full article online here.
CCS is probably most often recommended for those with genetic disorders, women over 40 doing IVF, women with poor egg quality), and in cases of recurring miscarriage. This option is particularly attractive for women of advanced maternal age who many not be producing as many eggs and are at a higher risk of aneuploidy embryos (experts say as many as 60% of miscarriages are due to aneuploidy).
I am currently working with a clinic in Europe (Prague) that will do CCS on embryos for a per embryo fee of approximately $500. Whereas paying the typical $5000+ fee in the US for CCS testing might not be as cost effective if you only have a few embryos; paying $500 for testing a single embryo to improve success rates and reduce miscarriage rates seems like a reasonable and affordable consideration. This option requires a biopsy and freezing of the embryos pending the results in about 2 – 3 weeks; then planning a transfer in a frozen cycle. While in the past, the best results were typically expected from fresh embryo transfer cycles; when using CCS to select embryos, we routinely see success rates of a frozen embryo transfer of a CCS tested embryo typically exceed the fresh transfer success rates. Further, a few recent studies referenced here, here and here are showing improved overall outcomes after a frozen embryo transfer.
I continue to be in awe and amazed at the advances in technology for IVF in the past decade. We are so fortunate to be living in this time and have this additional information to help improve the odds of having a baby for those who are suffering with infertility.