IMSI (Intracytoplasmic Morphollogicaly-selected Sperm Injection) is used for an exhaustive morphological selection of the spermatozoids that will fertilise the oocytes in an IVF cycle.
Once the spermatozoids are selected based on motility criteria, they are studied under a particularly powerful microscope for analysing the internal morphology and selecting the optimum ones for carrying out the fertilising.
IMSI could be an option after several failed IVF cycles and in some cases of severe teratospermia. It is not a technique that is recommended for everyone, as it has some drawbacks, like the considerable length of the procedure. In the specific cases where its efficiency is proved, it is considered to increase the implementation and child rate and reduce the rate of abortion.