What is ICSI?
Intracytoplasmic sperm injection, or ICSI, involves injecting a single live sperm directly into the center of a human egg. The technique was developed to help achieve fertilization for couples with severe male factor infertility or couples who have had fertilization failure in a previous in vitro fertilization (IVF) attempt. The procedure overcomes many of the barriers to fertilization, and allows couples with little hope of achieving a successful pregnancy to potentially obtain fertilized embryos.
A cycle of ICSI requires the female partner to undergo controlled ovarian stimulation (COS) so that more than one egg containing follicle develops. These follicles are aspirated using transvaginal ultrasound, and an embryologist will collect the eggs from the follicular fluid. The eggs are incubated in the embryology laboratory under specific conditions, while the semen sample is prepared. The outcome of the semen preparation is to separate the live sperm from the seminal plasma, dead sperm and debris, and this is done by centrifuging the sample through a special medium. Prior to the ICSI procedure, the embryologist will remove the support cells that surround each egg so that the eggs can be seen in more detail. Eggs that have reached the correct stage of maturity will undergo ICSI. This involves the embryologist picking up a single live sperm with a fine glass pipette and injecting it directly into an egg. This is repeated for each mature egg.