Insemination and Fertilization

In the laboratory, the mature eggs that have been aspirated are isolated.

• The embryologist removes the cells that normally surround an aspirated egg, then
• The 'cleaned' eggs are placed into a laboratory dish containing culture medium,    until they are ready for insemination (the process of bringing the egg and sperm    together).
In conventional IVF, insemination consists in putting each egg into a droplet of medium containing 100,000-500,000 sperm cells, in the hope that at least one sperm will penetrate and fertilize the egg.

However, insemination is done through ICSI (intra-cytoplasmic sperm injection) in case of

• A known male factor
• History of previous fertilization failures
• History of multiple IVF failures
• A patient older than 37
• A patient who has not conceived for more than 3 years despite open tubes and   normal semen analysis

In ICSI, one sperm is directly injected into each mature egg that is retrieved. This results in much better fertilization than conventional IVF, especially in the above-cited cases.