Blastocyst transfer is the embryo transfer performed on day five or six of embryo development and when the embryos have reached the blastocyst stage. The success rates of blastocyst transfer are very high and reach 65%.
During IVF the oocytes are retrieved from the woman and are fertilised by sperm, the developing embryos are cultured in the embryology lab for a few days and are then transferred to the woman’s uterus. Traditionally, the majority of embryo transfers occured on day three of embryo development, when they are at the cleavage stage. Recently, and following the development of new culture media that allow longer culture, embryos can be cultured in the lab until day five or six and reach the blastocyst stage.
The advantages of blastocyst transfer include the fact that the embryo and the endometrium are synchronised for implantation, as natural implantation occurs between day six and twelve of development. Moreover, due to extended culture, only those embryos with a better developmental potential are chosen for transfer.
Analysis of all the studies performed on embryo transfer showed that the pregnancy rate is higher following blastocyst transfer than that following transfer at the cleavage stage .
In our Centre the success rates reach 65% in women under 35. Our success rates are comparable to those reported in the scientific and medical journal worldwide.
- Glujovsky D., Riestra B., Coscia A., Boggino C., Comande D., Clapponi A. 2012. Cleavage stage versus blastocysts stage transfer in assisted reproductive technology. Cochrane Database Syst Rev. 7:CD00211