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.