One of the most important aspects in the success of an IVF cycle is the selection of those embryos with the highest developmental and implantation potential. A reliable selection procedure will enable fewer embryos to be replaced in each cycle, thereby reducing the incidence of multiple pregnancies whilst maintaining an acceptable pregnancy rate. At present, the most widely used methods of selection are based on morphological criteria. However, these methods may be imprecise. Chromosomal aberrations within embryos are relatively common and may be compatible with development beyond the stage at which embryo transfer normally occurs. More invasive selection methods, such as aneuploidy screening, may improve implantation and pregnancy rates, particularly for older women, but these techniques present their own ethical dilemmas.
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