Blastocysts: Pros and Cons

摘要

Blastocyst culture is not a new technology. Indeed the first IVF pregnancy was conceived following blastocyst transfer, although it ended in a spontaneous abortion (1). Several investigators have discussed the potential advantages of blastocyst transfer (2; 3; 4). However, with the use of a single medium formulation, with or without coculutre, blastocyst transfer did not significantly increase implantation rates compared to those obtained following embryo transfer on day 3, and has therefore not been embraced by the IVF community. In contrast, the relatively recent introduction of sequential culture media (5) has led to increases in blastocysts implantation rates (6; 7; 8). Therefore there is renewed attention on the role of the human blastocyst in IVF.