Blastocyst Transfer

What is a blastocyst?

About 5 days after the fertilization, blastocysts hatch by coming out from their outer layer (zona pellucida). With the recent advances in the field, embryos can be kept in the laboratory until this developmental stage. Embryo transfer in blastocyst stage is more advantageous because it is quite parallel to the time when the embryo falls in the uterus naturally (in vivo). Prerequisite for this method is to have at least 3 good quality embryos, 3 days after fertilization.

The egg is fertilised following ovulation from the ovary and the embryo goes on to divide (cleave) as it travels along the fallopian tube. Blastocyst formation occurs as the embryo reaches the uterus.