Blastocyst is one of the stage in embryo growth and development where the embryos are of day5 having high potential to achieve pregnancy. In this stage of embryo, they show significantly higher implantation rate as duration of the embryo exposure to the uterine cavity is providing analogous environment similar to natural cycle and allowing self-selection property of embryo to get activated after Day3 activation of embryonic genome.
Blastocyst embryos are cultured in IVF laboratory after pronuclear stage till day5 once fertilization is done via IVF/ICSI. During these fertilization process embryos start dividing from 2-4 Cell stage (Day2), 8 Cell stage (Day3) and Morula/Compacted (day4). This development occurs in an incubator closed system where temperature and gas level are maintained to a certain level that is synonymous to human body. The blastocyst stage of embryo has an outer trophectoderm layer and inner with inner cell mass(ICM) which collectively form fetus and its companion elements required during implantation.
What are the benefits of blastocyst transfer?
Blastocyst transfer has a higher chance of implantation as compared to the cellular stage as it is the initial stage where all potential changes and transformations occur during the developmental stage of embryos. Also, a single healthy and ‘A’ grade has a high capability to give a good outcome of pregnancy among females going IVF treatment. But there are few exceptional cases where a female being of age >40 years and already having multiple stimulation cycles still cannot conceive can choose blastocyst transfer. Implantation of blastocyst transfer is synonymous with the natural process of conception as the duration of implantation decreases. Behind this, there is a logical reason which is during the cellular stage the embryo remains in the uterus freely getting ready for implantation, after a few days it gets embedded in the uterine line and initiates embryo implantation.
There are some benefits to day5 blastocyst transfer
1. Higher pregnancy rate
2. Increases chances of pregnancy
3. Avoidance of multiple pregnancies
4. Significant/no obstetrics complications
5. Less implantation duration
Above all mentioned advantages still, there are some categories of females having infertility issues along with other medical conditions such as fibroids, endometriosis, and damaged fallopian tube shows lower pregnancy outcomes in such conditions though the selection of best quality embryo transfer also gives poor/no result post transfer.