The success rate of frozen blastocysts is relatively high and varies somewhat depending on the condition of the pregnant woman. Blastocyst is a transferable embryo that is formed after 3 days of in vitro culture and continues to be cultured in vitro until 5 days to form a blastocyst. At the blastocyst stage, the embryo has begun to differentiate into the trophoblast cells and the inner cell mass. The trophoblast cells develop into the placental portion of the embryo, and the inner cell layer will differentiate into the fetal portion. Blastocysts are embryos that have reached a certain stage of development. Compared to day 3 cleavage stage embryos, blastocysts are further cultured and screened out, and are of higher quality and higher differentiation potential, with higher implantation rate, higher developmental potential, and higher transfer success rate. Frozen blastocyst transfer is relatively free to choose the time of transfer compared to fresh embryo transfer, and thawing and transferring after adjusting the patient’s uterine environment and creating good conditions for implantation of gestational capsules can often improve the success rate of the transfer, which varies among different pregnant women with different conditions.