A "blastocyst" is a fertilized egg in its beginning stages. The Blastocyst Transfer procedure enables several embryos to develop over an extended period of time in the laboratory (five days, rather than two to three). The embryologist analyzes these blasts, and then selects the most qualified and healthiest one to significantly increase the chance of a successful pregnancy.
One of the great distinctions of this method is the goal of achieving one healthy child, rather than twins, triplets, or more. Numerous couples undergoing IVF incur the risk of multiple gestations, as they may wish to maximize their chances of pregnancy. Thus, multiple embryos are transferred, which raises the probability of multiple pregnancies. However, since only one embryo is physically transferred back into the uterus with a Blastyocyst Transfer, the chance for multiple gestations is virtually eliminated.