Patient's question:
In the morning of that day, two blastocysts that had been cultured for five days were transferred, but the doctor said there were still a few blastocysts that needed to be cultured for one more day. I want to know the difference between blastocysts cultured for five days and six days.Doctor's answer:
Five-day blastocyst and six-day blastocyst represent the developmental stage of the blastocyst. A five-day blastocyst is one that is currently hatching, while a six-day blastocyst is fully hatched. Both are relatively fragile because they lack the protection of the zona pellucida and are prone to death or damage during the freezing and thawing process. In China, due to technical reasons, the third-day blastocyst is often used for transfer. However, the United States has the world's top-tier embryology laboratories, enabling it to culture embryos to the fifth day for transfer.