Embryo culture as a diagnostic tool.

Embryo culture can serve as a strong diagnostic tool, yielding useful information regarding the implantation potential of the human embryo. The information thus gained is useful for quality control of the embryology laboratory, success rates of the IVF/intracytoplasmic sperm injection (ICSI) programme, and counselling of the couple following failed cycles. Zygotes can be scored and zygote quality has been associated with further embryonic development and cleavage stage embryo quality. Early cleavage, cleavage rate, cleavage stage embryo grade and subsequent progression of these embryos to the blastocyst stage have all been shown to be individual and collective markers for the implantation-competent human embryo. This manuscript discusses embryonic markers of normality/quality throughout in-vitro culture starting with the zygote and ending with the blastocyst.