Before ICSI can be done, mature eggs must be retrieved from the female partner during a standard IVF cycle. The male partner’s semen sample is prepared in the lab to isolate as many healthy moving sperm as possible.
After allowing the eggs to rest for two to three hours following their removal, the tight outer coating of cells (cumulus) is removed from each egg. Only then can we be sure the egg is mature enough to undergo ICSI.
Immature eggs cannot be injected. However, they can be incubated for a further two to six hours and reassessed. If they mature in that time they can still be injected along with the other mature eggs. A special instrument is used to hold the egg in place. It is so small you can barely see the tip with the naked eye.