Blastocyst transfer

Three days after fertilization, a normally developing embryo will contain about six to 10 cells. By the fifth or sixth day, the fertilized egg is known as a blastocyst — a rapidly dividing ball of cells. This term describes the process when the embryos grow for longer in the laboratory, and undergo critical developmental changes before being returned to the womb. This period of extended culture helps the experts select the most competent embryo(s) for transfer, and can help to indicate which embryos have the best growth potential. Therefore, blastocyst culture maximizes the chance of achieving a viable pregnancy.