The concept of Embryo Banking/Stockpiling: Embryo Banking offers a potential alternative to IVF with egg donation, for older women and those with DOR who wish to minimize the relentless effect of the “biological clock”. The process involves undergoing several IVF stimulation/egg retrieval procedures in relatively quick succession, biopsying them for preimplantation genetic sampling (PGS/PGT-A) and then freezing/banking all those that survive to the blastocyst stage (day 5-6 post-fertilization) embryos for future dispensation, rather than having them transferred to the uterus immediately. Once enough biopsied embryos (usually 4-8) have been stockpiled, all biopsied material derived from those embryos that reached the blastocyst stage are dispatched for PGS/PGT-A testing by generation gene sequencing-(NGS). Those embryos found to have a normal number of chromosomes (euploid) are held for subsequent transfer to the uterus in a later FET cycle (i.e. “staggered” embryo transfer). ”Such embryo banking/stockpiling” literally stops the biological clock in its tracks, allowing for the subsequent elective thawing of one or two frozen embryos at a time in future frozen embryo transfer (FET) cycles. This process would avert the risk of progressive declining egg/embryo “competency” over time.
Embryo banking/stockpiling would not have been feasible a decade ago since it was not until quite recently that we became able to reliably identify chromosomally normal (“competent”) embryos for selective banking. Embryo freezing technology also evolved dramatically over that time. Just a few years ago, the freezing process took a serious toll on embryos, severely damaging up to 50% of them in the freeze/thaw process. But that was then…Today, through embryo karyotyping with NGS for the selection of euploid embryos we are able to much better identify “competent” embryos for banking and stockpiling. In addition, the recent introduction of much improved egg/embryo freezing through ultra-rapid cryopreservation (or possibly even improved) eliminates most of the potential damage incurred to “competent” embryos during the freezing and thawing process. In fact, in IVF centers of excellence, the frozen embryo transfer (FET) process using vitrified/thawed embryos now yields at least the same IVF success rate as when fresh embryos are transferred!
These innovations (PGS/PGT-A and blastocyst Vitrification) have not only made embryo banking/stockpiling feasible, but have rendered the approach a most appealing option for older women and women with DOR who seek to undergo IVF using their own eggs.
This having been said, PGS/PGT-A is not an indispensable part of embryo banking. The process can be done without it, but, given the inevitability
GS of an age-related increase in the incidence of chromosomal abnormalities in the egg/embryo, it would be impossible for patients to know whether they have stored the most “competent” embryos and thus which ones to transfer to the uterus for the best chance of success when the time comes.