IVF ICSI Procedure - Important things you need to know

The basic idea behind IVF is that the eggs are removed from the ovaries and fertilized outside of the body in the laboratory. There are two techniques for fertilizing eggs. The older method is called standard insemination. With this technique, a few thousand sperm are placed in a laboratory dish near the egg. The sperm have to penetrate the egg on their own. This method has largely been replaced by ICSI.



ICSI stands for Intracytoplasmic Sperm Injection. With this technique, a single sperm is injected into a single egg. There are a number of reasons why ICSI is preferred over standard insemination. First of all, if a man has low sperm counts or poor sperm movement then the chances are higher that fertilization will fail. Sometimes, standard insemination can fail even when the sperm numbers are normal. This is likely due to a specific problem with the sperm not being able to fertilize eggs on their own. Unfortunately, we are not able to predict ahead of time which men have sperm that might fail to fertilize an egg. ICSI bypasses those types of problems,  so the chances of an IVF cycle failing because of fertilization failure is a lot lower with ICSI than with standard insemination.



When an egg is removed from the ovary it is surrounded by a dense group of cells called cumulus cells. These cells make it difficult to see the egg under the microscope. This makes it harder to determine if the egg is mature or not. Immature eggs cannot be fertilized. So when there is poor fertilization, it could be in part due to there being many immature eggs rather than a problem with the sperm



When we do ICSI, these cumulus cells are stripped away. This allows us to know with certainty whether an egg is mature and allows more precise evaluation of the egg retrieval.



Finally, ICSI is needed when we are doing genetic testing on embryos. With standard insemination, there may be sperm that didnt fertilize the egg still stuck to the outside of the egg after fertilization. This can cause an incorrect result  when trying to do genetic testing of the embryo so ICSI is mandatory when doing genetic testing.