ABSTRACT
To make single-embryo transfer an acceptable treatment, the advantages should outweigh the disadvantages. The arguments in favor are obvious: no multiple pregnancies and consequently fewer complications for mother and child(ren). This means less mortality, less morbidity and fewer disabled children. Arguments against single-embryo transfer seem very strong, however. If we compare the few papers that have been published on the implementation of single-embryo transfer with the overwhelming majority of papers in which two, three or more embryos are transferred, we must conclude that only a few centers are convinced of the feasibility of single-embryo transfer. The arguments against single-embryo transfer are mainly economic. The only way to refute these arguments is to optimize single-embryo transfer to such an extent that it becomes at least a competitive and eventually the most cost-effective treatment. This chapter focuses on optimization of the laboratory procedures and of the transfer procedure as prerequisites for single-embryo transfer in an assisted reproduction technologies (ART) program with a stable high implantation rate. Reduction of the number of embryos transferred is required to establish a one-to-one link between embryo and outcome. In these conditions an evidence-based selection system can be developed that relies exclusively on embryos with a documented outcome.
