Intracytoplasmic Sperm Injection
What is Intracytoplasmic Sperm Injection?
Intracytoplasmic sperm injection (ICSI) is a modification of the IVF procedure. While IVF involves the mixing of sperm with eggs under laboratory conditions, ICSI is a more sophisticated technique in that it involves the injection of one sperm into the egg. ICSI is carried out using a specialised piece of equipment known as a ‘micromanipulator’ by embryologists who hold a license to perform this technique.
Embryologist injecting a sperm into an egg
Who is ICSI suitable for?
There are two main groups of patients who may be helped by ICSI. They are: -
- Those couples where the male partner has a low sperm count, reduced sperm motility, an increase in the number of sperm with an abnormal appearance, or where there are antisperm antibodies, that cause sperm to stick together.
- Those couples who have had failed IVF treatment.
ICSI can also be used with surgical sperm recovery techniques such as PESA or TESA.
What does ICSI involve?
ICSI follows normal IVF procedures up to the point of egg collection and sperm preparation. With ICSI, the eggs are then carefully separated from the surrounding cumulus cells to check their suitability for injection. Eggs must be injected at the correct stage of maturity and therefore it is usually not possible to inject all the eggs collected. The embryologist will let you know how many eggs are suitable for injection. Those eggs that are unsuitable for injection may then be mixed with the sperm as in normal IVF procedures, but these eggs rarely fertilise.
The ICSI injection process involves holding a single egg by gentle suction at one end of a microscopic tube and then picking up and injecting a single sperm into the centre of this egg using an even finer glass pipette. The eggs are then left overnight in the incubator for fertilisation to hopefully proceed. The next day the embryologist assesses the eggs for fertilisation.
Two days after the egg collection and ICSI, the fertilised eggs (embryos) are assessed again for signs of continued division and the best are selected for transfer into the womb. To allow monitoring of this technique, all the embryos replaced must be from either injected eggs (ICSI) or straightforward IVF, the two cannot be mixed. Embryos not used can be frozen for later use providing they are suitable (your embryologist will advise you at the time of transfer). Unfortunately, although ICSI can greatly improve chances of fertilisation it cannot be guaranteed. Although most patients will have embryos suitable for transfer some couples may be unlucky and all the eggs may fail to fertilise.
ICSI Microscope with dish containing eggs & sperm
What are the risks associated with ICSI?
Since ICSI involves placing a glass needle into your egg and injecting the sperm directly into its centre you may have concerns about the risk of damage to the embryos, or to any abnormalities in the babies born from this technique. As this technique is relatively new, all the risk factors cannot be determined accurately and the long-term risks will not be known for a number of years. However, data from the centre in Brussels where this technique was first performed show that the incidence of major birth defects in children born as a result of ICSI may be twice that of normal, though this is still an extremely rare occurrence.
Minor birth defects may also be 50% more likely. Abnormalities involving sex chromosome abnormalities occur quite frequently naturally (around 1 in 200- 300 births) and are likely to be increased slightly in ICSI babies. Although this means that problems are still very rare, we do offer a blood test to the male partner to check his chromosomes.
It has been found that some men with low sperm counts may have a fault on their Y chromosome that cannot be detected by the standard chromosome tests. These men who achieve a pregnancy with ICSI may pass this fault on to their male children who as a result may have a low sperm count in later life.
We would be happy to discuss any concerns you have about this treatment.