Intra-Cytoplasmic Sperm Injection (ICSI)
What is ICSI and how does it work?
ICSI is a type of IVF (In vitro fertilisation) treatment that
involves drawing up a single sperm into a very fine glass needle
and injecting it directly into the centre of the egg.
The fertilised egg (embryo) can then be transferred into the
womb of the woman as in a normal IVF cycle. ICSI is a relatively
new technique (introduced into clinical treatment for certain types
of infertility in 1992), but has already helped many couples. The
live birth rates for ICSI and conventional IVF are similar.
This method bypasses any natural barriers that may have been
preventing fertilisation. For example, some cases of infertility
are due to the sperm of a male partner not being able to penetrate
the outer part of the egg to fertilise the egg.
The major development of ICSI means that as long as some sperm
can be obtained (even in very low numbers), fertilisation is
Is ICSI for me?
ICSI is often recommended if:
The male partner has a very low
Other problems with the sperm
have been identified, such as poor morphology (abnormally shaped)
and/or poor motility (poor swimmers).
At previous attempts at IVF
there was either failure of fertilisation or an unexpectedly low
The male partner has had a
vasectomy and sperm have been collected from the testicles or
epididymis (sperm reservoir).
Other situations where the
sperm count is zero and donor insemination is not wanted.
The male partner does not
ejaculate any sperm but sperm have been collected from the
The male partner has had
problems obtaining an erection and ejaculating. This includes men
with spinal cord injuries, diabetes and other disorders.
When there are high levels of
antibodies in the semen.
When there have been previous
What does ICSI involve?
ICSI is similar to conventional IVF in that eggs and sperm are
collected from each partner. To achieve fertilisation, a single
sperm is taken up in a fine glass needle and is injected directly
into an egg. The eggs are then incubated and examined. Usually one
or two embryos may then be transferred back into the womb of the
woman two or three days after fertilisation. Some eggs may not
survive the injection process and not all eggs collected will be of
a high enough quality or mature enough to be suitable for
What are the risks of ICSI?
Because ICSI is a relatively new treatment, it is not yet known
whether there is any risk that injecting the sperm into an egg
could damage it, with possible long-term consequences for the
The risks that have so far been associated with ICSI are:
- Certain genetic and developmental defects in a very small
number of children born using this treatment. However, problems
that have been linked with ICSI may have been caused by the
underlying infertility, rather than the technique itself.
- The possibility that a boy conceived as a result of ICSI may
inherit his father's infertility. It is too early to know if this
is the case, as the oldest boys born from ICSI are still in their
- An increased risk of miscarriage because the technique uses
sperm that would not otherwise have been able to fertilise an
- A low sperm count caused by genetic problems could be passed on
to a male child, so you may want to undergo genetic tests
before going ahead with ICSI.
- Infertile men with low sperm count or no sperm in their
ejaculate may be tested for cystic fibrosis genes and for
- You may want to discuss the full implications of taking these
tests with your clinician or the clinic's counsellor before going
Inheritance of cystic fibrosis gene mutations
Some men who have no sperm in their semen are found to have
congenital bilateral absence of the vas deferens (CBAVD). In this
condition, the tubes that carry sperm from the testes to the penis
are missing. Two thirds of men with CBAVD are also carriers of
certain cystic fibrosis mutations. Men with CBAVD and their
partners may therefore wish to undergo genetic testing before
proceeding with ICSI. You can be referred to Genetics Department
for more information and counselling about the implications of
Intra-Cytoplasmic Sperm Injection (ICSI)