What is intra-cytoplasmic sperm injection (ICSI)?
ICSI involves injecting a single sperm directly into an egg in order to fertilise it.
Is ICSI for us?
ICSI is often recommended if:
- the male partner has a very low sperm count
- other problems with the sperm have been identified, such as poor morphology (abnormally shaped) and/or poor motility (poor swimmers)
- at previous attempts at in vitro fertilisation (IVF) there was either failure of fertilisation or an unexpectedly low fertilisation rate
- the male partner has had a vasectomy and sperm have been collected from the testicles or epididymis (sperm reservoir)
- the male partner does not ejaculate any sperm but sperm have been collected from the testicles
- the male partner has had problems obtaining an erection and ejaculating.
How does ICSI work?
An embryologist will examine your sperm under a microscope and decide whether ICSI could increase your chances of fathering a baby. The major development of ICSI means that as long as some sperm can be obtained (even in very low numbers), fertilisation is possible.
If you can, you produce a fresh sperm sample on the same day as your partner’s eggs are collected.
The procedure for ICSI is similar to that for IVF, but instead of fertilisation taking place in a dish, the embryologist selects sperm from the sample and a single sperm is injected directly into each egg in order to fertilise it.
This does not mean that the egg is fertilised, but ICSI now gives an opportunity for that complex process to commence. ICSI is not a guarantee that fertilisation will take place.
What are the risks of ICSI?
Because ICSI is a fairly new treatment (it was introduced in 1992), 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 child. 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 early teens.
- An increased risk of miscarriage because the technique uses sperm that would not otherwise have been able to fertilise an egg.
- 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 chromosome abnormalities. You may want to discuss the full implications of taking these tests with your clinician or the clinic’s counsellor before going ahead.
- It is unlikely that all the eggs collected will be suitable for ICSI, as only mature eggs can be injected. Typically about 70 or 80 out of 100 (70%-80%) of eggs collected are mature. On average about 70 out of 100 (70%) of the eggs will fertilize.
- As ICSI involves using a needle to inject the sperm into the egg it is possible that some eggs will be damaged by the procedure and will not fertilize.
Do any factors affect the success rate of ICSI?
Female factors – in order to withstand the injection process, eggs need to be fairly robust (tough) and of good quality. It is known that the egg quality is reduced in older women and in women who smoke. The success rates of ICSI and IVF are lower in older women (older than 38 years) and women who smoke.
Male factors – if there are no moving sperm present in the sperm sample, it is difficult to identify live sperm. Under these circumstances it may be necessary to select a non-moving sperm for injection. A large number of these sperm will be dead and therefore fertilisation rates will be poor under these circumstances. There is also some evidence that injecting sperm with abnormal head shapes may be associated with poor results.