Since we culture all embryos in the embryoscope, we cannot only see how the embryos look the next morning, but also how cell cleavages occurred during the night. This helps us identifying the embryo with the greatest implantation potential.CleavagesTwo days after oocyte retrieval, the embryos are once more examined in the embryoscope. First at this stage, the embryologist is able to tell something about embryo quality, and the chance of giving rise to a pregnancy.The optimal embryo has now cleaved into 4 cells of equal size, and there is a visible nucleus in each cell. The embryologist investigates the timing and the synchrony of cell cleavages. In addition, she also looks at the number of small fragments inside the zona pellucida, which represent sequestered cellular material. If there are many fragments, the embryo is not suitable for freezing. The video demonstrates how embryo development looks in the embryoscope.