ICSI – Intra Cytoplasmic Sperm Injection
WHAT IS ICSI?
ICSI is very similar to conventional IVF in that gametes (eggs and sperm) are collected from each partner. The eggs are fertilised in the laboratory and the resulting embryos are cultured in the laboratory until the best one or two are selected for transfer to the woman’s uterus 2 to 6 days later. The difference between the two procedures is the method that is used to achieve fertilisation.
In conventional IVF, the eggs and sperm are mixed together in a dish and the sperm fertilises the egg ‘naturally’. However to have a chance that this will occur, very large numbers of actively swimming normal sperm are required. For many couples, the number of suitable sperm available may be very limited or there may be other factors preventing fertilisation, so conventional IVF is not an option. ICSI has provided hope for these couples.
ICSI refers to the laboratory procedure where a single sperm is picked up with a fine glass needle and is injected directly into each egg (Figure 1). This is carried out in the laboratory by experienced embryologists using specialist equipment. Very few sperm are required and the ability of the sperm to penetrate the egg is no longer important as this has been achieved by the ICSI technique. ICSI does not guarantee that fertilisation will occur as the normal cellular events of fertilisation still need to occur once the sperm has been placed in the egg.
The first pregnancies following ICSI were reported in 1991 and the first baby was born in 1992. Since then ICSI has become widely used in fertility clinics worldwide.
WHO IS ICSI SUITABLE FOR?
Circumstances in which ICSI may be appropriate include:
- When the male’s sperm count is very low.
- When the sperm have poor motility or are in other ways abnormal.
- When the sperm has been retrieved surgically from the epididymis (MESA / PESA) or the testes (TESE / TESA), from urine or following from retrogade or electro-ejaculation.
- When there are high levels of antisperm antibodies in the semer.
- When there has been a previous failure to achieve fertilisation using conventional IVF.
WHAT DOES ICSI INVOLVE?
From a patient perspective, undergoing an ICSI treatment cycle is exactly the same as a conventional IVF cycle and the same steps are involved. Briefly these steps are:
- Pituitary down regulation followed by stimulation of the ovaries to produce a number of follicles and to encourage development and maturation of the eggs.
- Retrieval of the eggs by the doctor in theatre.
- Preparation of the male sperm sample in the laboratory.
- Insemination of the eggs in the laboratory and culture of the resulting embryos.
- Transfer of the embryos back into the uterus.
HOW SUCCESSFUL IS ICSI?
More than 95% of patients have at least some eggs fertilised. In most cases this would not have been possible without the use of ICSI. The fertilisation rate following ICSI is about 70% on average.
Chances of success vary between patients, particularly according to the age of the woman, but worldwide, about 25% of patients will have a baby after one attempt at ICSI.
ARE THERE ANY IMPLICATIONS OF ICSI FOR THE CHILDREN BORN AS A RESULT OF THIS FORM OF TREATMENT?
This is naturally a concern to parents having fertility treatment and there has been a good deal of media attention. Overall the consensus from recent medical literature suggests that the risks are the same as for conventional IVF.
However there are some issues to be aware of that may be related to the underlying male infertility problem, rather than being caused by the ICSI treatment that is being used to resolve this problem.
It is sometimes difficult to separate these two effects, but the distinction is important because there is little that can be done to influence any genetic effects of the underlying male infertility problems.
- Congenital Bilateral Absence of the Vas (CBAVD)
Some men are infertile because they do not have a vas deferens. This is the duct that transports sperm from the testicle to the base of the penis. Without a vas, the sperm, which are created in the testicle, cannot get out and total male infertility results. There are no sperm at all in the ejaculate.
Men with CBAVD are also more likely to carry the cystic fibrosis gene and there is a risk this may therefore be passed on to any children.
It is possible to be a carrier of the cystic fibrosis gene without having congenital absence of the vas or cystic fibrosis, and the connection between the conditions is obscure. If we suspect you have congenital bilateral absence of the vas deferens this will be discussed in detail, and testing for cystic fibrosis may be recommended. As the cystic fibrosis gene is quite common in the general Caucasian population (about 1:25 people are carriers), your partner may also need to be tested to assess the risk of passing on cystic fibrosis to any children born.
- Deletions on the Y Chromosome
Men with a very low sperm count (less than 1 million sperm per ml) may have an abnormality in the Y chromosome, which only exists in the male. The incidence is quite low. This means that any son born to a man who carries a deletion on his Y chromosome (whether by IVF or ICSI or natural conception) may have the same problem as their father. Chromosome testing is available to see if the sub-fertile man does indeed carry a minor abnormality on his Y chromosome.
Again this problem appears to relate to the underlying infertility problem rather than to ICSI. Most patients having ICSI still prefer to use their partner’s sperm rather than donor sperm, which is the only other alternative.
- Other Chromosomal Abnormalities
There appears to be a small increase in the risk of chromosome abnormalities among children born following ICSI. This may affect either the sex (X and Y) chromosomes or the other chromosomes, which are called autosomes. The increase over and above that to be expected in the general population is very small. The overall incidence following ICSI treatment is reported to be 1.6%, which compares favourably with the expected incidence of 0.8%.
Again this seems to be a problem arising from underlying male infertility, rather than from the ICSI procedure itself. This especially applies to sex chromosome abnormalities, which are more common when the semen analysis is severely abnormal. As this increase is only 0.9% compared with 0.3% in the normal population, most couples still prefer to use their partner’s sperm with ICSI.
- Congenital Abnormalities
All parents face the risk that there may be something wrong with their child at birth – a congenital abnormality. The risk is around 2 to 2.5%. Occasional research papers have suggested that the risk of having a congenital abnormality following ICSI may be higher than for IVF, and the general fertile population. However current consensus in medical literature and notably the opinion of the expert Belgian group working in the University of Brussels who first perfected the ICSI procedure, is that the risk of a congenital abnormality following ICSI is the same as in the general population and the IVF population.
The above ‘risk’ information is intended to be informative. In general, the areas of concern appear to relate more to the underlying problem rather than to the technique of ICSI itself.
ICSI has proved to be an invaluable treatment for couples with male factor infertility and in the vast majority of patients with male infertility there is no other effective treatment.
Our medical and scientific staff are available to answer any questions you may have relating to this treatment. As with all our patients we wish those having IVF treatment with microinjection every success.
For more information or queries regarding any of the services offered at Life Fertility Clinic, please contact us.