Causes related to the Embryo
* Embryo viability is a crucial factor in achieving pregnancy, in fact ICSI success over other treatment modalities lies in the fact that embryo is achieved and assessed
*The reason behind the ovarian stimulation is to achieve many eggs so that more embryos are reached; followed by the selecting the best embryo.
* Until recently embryologists (the scientist in IVF lab) select the best embryo depending on the way the embryos shape. This has been found to be not true.
* In a later stage, embryologist started in selecting embryo that were proven to be more dividing as an indicator of vitality, by transferring embryos that have reached day 5 and called then blastocyst.
* Recently, embryologist were able to select the embryos that have the right number of chromosomes, by taking a biopsy from the embryos.
* Embryo biopsy started by taking a cell or two from day 3 embryo (when the embryo is about cells), but the procedure was found to be hazardous to the embryo and affect embryo implantation by 40%.
* Lately, a more successful biopsy was studied throughly and found not to affect embryo vitality and in the same time can select the embryo that has the right number of chromosomes.