ICSI allows couples with very low sperm counts or poor quality sperm (including low motility, abnormally shaped sperm) to achieve fertilization and pregnancy rates equal to traditional IVF. It is also an option for couples who have not achieved fertilization in previous IVF attempts or have low egg number or egg abnormalities.
Once the follicular fluid is removed from the follicle, the eggs are placed into an incubator. The eggs are to be fertilized with sperm later the same day. The male partner will provide a semen sample by masturbation from which the healthiest sperm will be extracted. If no sperm are available in a natural way, your embryologist may schedule a sperm retrieval procedure such as testicular biopsy, microdissection, testicular sperm extraction (TESA) or percutaneous sperm aspirations (PESA) around the time of egg retrieval.
During conventional fertilization approximately 50,000 sperm are placed with each egg in a culture dish and left together overnight to undergo the fertilization process. The ICSI technique is used to fertilize mature eggs directly. Under the microscope, the embryologist picks up the best single sperm and injects it directly into the cytoplasm of the egg using a small glass needle. Until recently, embryos were cultured for three days and then transferred to the uterus and/or cryopreserved (frozen). Now it's recommended to grow the embryos for five or six days until they reach the blastocyst stage. For some couples these blastocysts may have a greater chance of implantation, allowing embryologists to transfer fewer embryos and lower the risk of multiple births while increasing the chance of pregnancy. On day two or three after fertilization, the embryos will be evaluated for blastocyst culture. If there is a sufficient number of dividing embryos they will be placed in a special solution and grown for two or three additional days.