ICSI is the injection of a single sperm directly into the egg using a specially prepared needle. It is recommended for severe cases of male infertility and where there has been no fertilisation following IVF previously.
With ICSI, very few sperm are required and the ability of the sperm to penetrate the egg is no longer important as this penetration is bypassed by the ICSI technique. It is important to remember that whilst ICSI is a technique used in the laboratory to help fertilisation occur, it does not guarantee it.
Couples go through the same preparatory processes as with IVF, namely ovulation induction and egg collection.
ICSI can only be carried out on a mature egg. Unfortunately egg maturity can only be truly identified under the microscope and it is, therefore, possible that following egg collection, none of the eggs are suitable for ICSI. This situation is fortunately rare.
A small percentage of eggs (fewer than 1 in 10) will be damaged by the injection process and the damage is evident at the time of the injection procedure. These eggs can no longer be used. Of the remaining eggs, however, on average 6 out of 10 are fertilised following the ICSI procedure. The fertilised embryos are allowed to develop as for standard IVF treatment prior to embryo transfer.
Does ICSI carry any risks to our baby?
ICSI, like IVF, is an invasive procedure. However, unlike IVF, ICSI involves injecting a sperm directly into an egg, therefore allowing the use of sperm that may otherwise not be able to fertilise an egg. For these reasons, concerns about the potential risks to children born as a result of ICSI have been raised and there have been a number of follow-up studies carried out.
ICSI is still a relatively new technique and children born as a result of ICSI are still very young. Consequently, these follow-up studies involve relatively small numbers of children and, therefore, the results to date are not conclusive. It has been suggested that ICSI is associated with certain genetic and developmental defects in a small number of children born using this treatment.
Inheritance of cystic fibrosis gene mutation
Men with very severe male infertility, where there is no sperm found in the semen, are sometimes found to have congenital absence of the vas deferens. Many of these men are also carriers of certain cystic fibrosis mutations. We therefore recommend that all men with azoospermia are tested to determine whether or not they carry this mutation.
Inheritance of subfertility
Some forms of severe male infertility do have a genetic link and it is possible that fathers may pass on their subfertility to their sons. This means that these children may also require infertility treatment to become parents.
There is no evidence to suggest that ICSI increases the chances of major birth defects. The number of babies reported to have major defects, such as a cleft palate, is similar in both the general population and those born following ICSI. There are some studies that suggest a slightly higher rate of minor abnormalities in the ICSI group, but more studies are needed to gain further insight into these possible effects.
We advise that all children conceived as a result of ICSI have regular developmental assessments.
Please keep us informed of the results as it is of particular importance to document any abnormal findings regarding the health and development of these children. This will help us to provide more accurate information to all of our couples.