ICSI (Intra-Cytoplasmic Sperm Injection)
What is ICSI?
ICSI is an acronym for Intra Cytoplasmic Sperm Injection. ICSI is a procedure carried out by licensed embryologists in the laboratory and is a more sophisticated technique compared to IVF. All aspects of an ICSI cycle are identical to an IVF cycle, with the exception of how the sperm is mixed with the egg. During IVF a portion of moving sperm is added to the eggs and left overnight to fertilise the eggs using the natural mechanisms. With ICSI, the natural fertilisation process is bypassed by injecting a single sperm directly into a mature egg.
A ‘micromanipulator’ is used to both hold the mature egg in position by gentle suction and inject the sperm into the egg. Specially made tools are used with the micromanipulator to help the embryologist. As such, the process does involve placing a fine glass needle into the egg to inject the sperm. The eggs are then incubated overnight and the next day checked to see if fertilisation has taken place.
Up until the point of egg collection, IVF and ICSI do not differ. This means patients will still be given drugs to stimulate the ovaries and will undergo egg collection. Some patients may undergo a natural cycle without the need for drugs where appropriate.
Cases where ICSI may be used
- Couples where the male has severe sperm abnormalities such as low sperm count, reduced sperm motility, a high number of sperm with an abnormal appearance or antisperm antibodies.
- Couples who have had previously failed IVF treatment because of failed fertilisation.
- Couples where the male has had sperm surgically retrieved.
- Women who use frozen eggs.
Risks and complications of ICSI
The risks of ectopic pregnancy, OHSS and the egg collection risks are the same as IVF, as are the risks of multiple pregnancy. There is also a chance the eggs will not survive the injection procedure. Approximately 95% of eggs injected will survive injection. The chance of fertilisation failure is lowered as a result of bypassing the normal fertilisation process. It has been reported that there is an increased risk of identical twins when using ICSI rather than IVF.
It has been reported that there are some genetic risks and a higher chance of birth defects associated with children born as a result of ICSI compared with natural conception. Published studies suggest this may be as a result of parental characteristics which have contributed to the fertility issues in the first place. Male offspring whose father’s have severe sperm abnormalities may inherit conditions and children conceived by ICSI appear to have more congenital abnormalities, particularly uro-genital defects. Many of these can be surgically corrected. A recent large study showed that this risk can be reduced to the same level as natural conception by freezing the embryos and undergoing a frozen embryo transfer instead of a fresh embryo transfer.
Overall the data is reassuring for the long term consequences for children born after IVF / ICSI.