ICSI treatment

Intracytoplasmic sperm injection (ICSI) is an insemination technique that may be incorporated into an IVF cycle. It involves injecting a single sperm directly into the centre of a mature egg. Fertility specialists may recommend ICSI to increase the chances of a successful IVF treatment cycle, particularly in instances of male infertility. They may also recommend ICSI if previous IVF cycles were unsuccessful.

Following egg collection and sperm retrieval, our embryologists seek to identify the highest-quality egg and sperm for use in the ICSI procedure.

First, they remove the support cells from around the eggs – these are the cells that nourish the egg throughout its growth and development. By doing this, they can identify the eggs that are mature and therefore, suitable for ICSI treatment. At this stage, our embryologists will also microscopically assess the motility, size and shape of the available sperm, so they can select the fittest sperm to inject into the mature egg.

Prior to injection, our embryologists will also examine the profile of the mature egg using a powerful microscope with polarised light. Specifically, they will look to identify the egg’s spindle – where the DNA is located. Research shows that mature eggs with visible spindles result in significantly higher rates of fertilisation, embryo formation and pregnancy, and thus represent better eggs to inject. Locating the spindle also enables the embryologist to determine the best position to inject the sperm into the egg. The embryologist will avoid injecting directly into the area of the spindle during the ICSI procedure to prevent damage to this vital structure.

Once a mature egg and sperm have been selected, the sperm is directly injected into the egg with extreme precision. This process facilitates fertilisation, as the sperm must no longer penetrate the egg’s outer cover. However, it still does not guarantee successful fertilisation.

ICSI is an advanced technique that may be recommended to increase the chances of a successful IVF cycle, particularly if male factor infertility is a contributing component. Male factor infertility refers to abnormalities of sperm quality, including their shape and movement, or lower numbers of sperm in a man’s semen (which is known as oligospermia). Your fertility specialist may also recommend ICSI if:

• A woman has fewer eggs available for fertilisation (to increase the chance of conception)
• Previous traditional IVF cycles were unsuccessful due to failed fertilisation
• The sperm are obtained through surgical sperm retrieval procedures
• Frozen or donor sperm are used
• An embryo is undergoing PGT testing – during fertilisation, only one sperm fertilises the egg; however, nearby sperm may get stuck to the outside of the egg, which can interfere with genetic testing results.

ICSI can increase the chances of successful fertilisation when needed. In traditional IVF, thousands of sperm are mixed with an egg in a laboratory dish, with the ‘fittest sperm’ fertilising that egg. In ICSI, we inject a single sperm into the egg, which may help to bypass obstacles related to fertilisation.

Like all medical procedures, ICSI has potential risks and benefits. Some risks specific to ICSI, include:

• Damage to a woman’s egg from the egg cleaning process and needle insertion – the risk of egg damage is very low¹
• Inheritance of male infertility if the child is male and ICSI was used to overcome male infertility in the setting of Y chromosome (genetic) abnormalities

Your fertility specialist would only recommend ICSI if the potential benefits outweighed the potential risks. However, it is important to consider these risks and benefits for your individual circumstances.

References:
1. European Society of Human Reproduction and Embryology (ESHRE) et al. The Vienna consensus: report of an expert meeting on the development of ART laboratory performance indicators. Reprod Biomed Online, 2017;35(5):494-510. doi: 10.1016/j.rbmo.2017.06.015

Your fertility specialist will usually recommend the transfer of a single embryo per IVF treatment cycle, and this includes ICSI treatment cycles. However, during an egg retrieval, we aim to collect 6–12 eggs because there is a chance that some eggs may not make it through to the embryo stage (we call this the IVF attrition rate).

Ideally, several eggs will successfully fertilise and reach the embryo stage, ready for implantation. You can also safely store any embryos not implanted in your current cycle for use in future IVF cycles if necessary.