In Vitro Fertilization (IVF)
Over the next few days, the embryologist monitors the smooth growth of fertilized eggs, now called embryos. Assessment and selection of embryos for continued culture and embryo transfer is based on two morphological criteria: the division (or cleavage) of the emb¬ryo into cells (blastomeres) and the morphological appearance of these cells. On the second day after egg retrieval, embryos must be divided into 2-4 cells, and on the third day they must reach the stage of 5-8 cells. The best morphology is presented by embryos without fragmentation, with a regular and uniform shape of blastomeres.
In addition to embryo morphology, the day for embryo transfer is also determined by the morphology of the endometrium and the perfusion of the woman’s uterus on the day of egg retrieval.