Embryo Transfer – Day 3 versus Day 5
CNY Fertility Center has locations in Syracuse, NY Albany, NY and Rochester, NY. CNY Fertility offers affordable fertility treatments including low cost IVF (In Vitro Fertilization). Patients often have questions about the day that their embryos will be transferred back to their uterus following their IVF procedure. This article is a quick summary of the history and advantages of both Day 3 and Day 5 embryo transfers.
Until about 10 years ago, all embryos were routinely placed in the uterus on day 3 of the cycle. Embryos are then at the 6-8 cell stage.
(8 celled embryo – Day 3)
Culture methods then emerged which allowed healthy embryos to continue developing to day 5, the blastocyst stage which has several attractive features. Most importantly it allows some of the embryos which are doomed to failure due to internal defects to fall by the wayside as they arrest and do not continue to develop. Thus the more hardy embryos are self selecting and the rate of implantation of each embryo is higher. Culturing embryos out to the blastocyst stage reduced the number of embryos that were transferred back as well, reducing the incidence of multiple gestations.
(Blastocyst stage embryo – Day 5)
Initially it seemed as this was applied in IVF practice, that the ability to choose the more robust embryos by self selection in this manner would raise pregnancy rates. In a common scenario, the choice if a patient had 5 embryos available for transfer, all about equal in quality on inspection under the microscope, the option would be to replace 3 embryos on day 3 or two on day 5. It was hoped that the day 5 embryo transfer would yield higher results for the IVF patient. This has not turned out to be the case. It is however true that the number of triplets is reduced by use of the day 5 strategy, which is an important option to consider when the risk of multiples is paramount.