Intracytoplasmic sperm injection (ICSI)

What is ICSI?

Intracytoplasmic sperm injection (ICSI) is a specialist fertility treatment that involves injecting a single sperm into an egg. It is a further development of IVF treatment that has revolutionised the treatment of male infertility problems.

When an egg is fertilised naturally, many millions of sperm cells are needed – they have to find the egg and penetrate its outer layers. For men with poor quality sperm this can make the chance of them fathering their own children naturally almost impossible.

The ICSI process

ICSI is a specialist technique that takes place as part of the IVF process. It is different to a normal IVF cycle because of the way the egg is fertilised.

As in IVF, the female partner will undergo hormone treatment to encourage multiple mature eggs to develop. These eggs are collected in a short day surgery procedure.

Then, the eggs are placed under a very powerful microscope, and an individual sperm cell is injected into each one, with very fine micromanipulation equipment. This is a very delicate procedure performed by highly skilled embryologists – the human egg is about 0.1mm in diameter, and the sperm is 100 times smaller than that.

Following injection, most eggs will fertilise and divide and multiply to form an embryo. The embryos are allowed to mature for about five days in the incubator, until they reach the blastocyst stage. One of the embryos is then transferred to the woman’s uterus with a thin, flexible needle, in a procedure much like a Pap test. It is left to implant and form a pregnancy. Extra embryos are frozen for future use, if you need them.