Intracytoplasmic sperm injection
What Is ICSI?
ICSI involves the collection of eggs directly from the ovaries, then the injection of a single sperm from the male partner into each mature egg to create embryos.
Who Can Benefit From ICSI?
ICSI is a treatment for male infertility and may be offered if:
- The sperm count is very low.
- The sperm are not mobile enough (i.e. they cannot swim properly)
- An attempt at In Vitro Fertilization (IVF) did not result in fertilization
- Sperm have had to be removed directly from the epididymis or testicle using a surgical technique.
How Is ICSI Carried Out?
On the day of ICSI, the embryologist carefully removes the outer (cumulus) cells from each egg, using an enzyme normally produced by sperm. This enables the embryologist to see inside the egg using a high powered microscope and assess if the egg is ‘mature’. All eggs can be inseminated by IVF, but only mature eggs can be used in ICSI. The sperm are prepared as normal for IVF. The embryologist then picks out individual live sperm, of normal appearance and injects one into each egg.
After ICSI the eggs are returned to the incubator overnight and checked for fertilization the following morning.
How Successful Is ICSI?
Approximately 6 out of every 10 eggs will fertilize successfully by ICSI, similar to IVF. The reasons for ICSI fertilization not being 100% successful include:
- Immature eggs cannot be injected.
- Some eggs may be damaged by the injection procedure. This appears to be related to the properties of the inner egg membrane.
- Even when injected directly into the egg, many sperm are not capable of ‘activating’ the egg.
Following successful fertilization, embryo development is similar for ICSI and IVF. Embryo transfer, pregnancy rates are similar to IVF.