Intracytoplasmic Sperm Injection (ICSI) is a highly specialised form of IVF in which a single sperm is selected and injected directly into the centre of a mature egg using an ultra-fine glass needle. The technique was developed in the early 1990s and transformed the treatment of male infertility, enabling fertilisation even when very few sperm are available or when sperm function is significantly impaired.
ICSI is performed by a senior clinical embryologist under a high-powered microscope, combining precision laboratory technique with the same ovarian stimulation and embryo transfer process as conventional IVF.
"ICSI removes one of the most significant barriers to fertilisation — ensuring the best sperm reaches the egg directly, regardless of how few are available."
How ICSI Differs from Conventional IVF
In standard IVF, eggs and sperm are placed together in a laboratory dish and fertilisation occurs naturally. ICSI bypasses this step entirely: a single sperm is captured with a hollow glass needle and injected precisely into the cytoplasm of the egg. This is particularly valuable when sperm quality or quantity is insufficient for natural fertilisation to reliably occur.
The ovarian stimulation, egg retrieval, embryo culture, and transfer steps are identical to conventional IVF — only the fertilisation method differs.
Who Is ICSI Recommended For?
Couples Who May Be Offered ICSI
- Severe male factor infertility — very low sperm count (oligospermia) or absent sperm in the ejaculate (azoospermia)
- Poor sperm motility (asthenospermia) or abnormal sperm morphology (teratospermia)
- Sperm retrieved surgically from the testis (TESA/PESA) due to blockage or absent vas deferens
- Previous failed or low fertilisation with conventional IVF
- Couples using frozen sperm that may have reduced viability after thawing
- Couples combining IVF with preimplantation genetic testing (PGT), where fertilisation reliability is critical
- Unexplained infertility where conventional IVF fertilisation cannot be guaranteed
The ICSI Procedure
Sperm Selection
On the day of egg retrieval, a fresh semen sample is collected and processed. Embryologists identify the most morphologically normal, motile sperm under high magnification for injection.
Egg Preparation
Mature eggs are identified and stabilised. The cumulus cells surrounding each egg are gently removed to allow direct visualisation and injection access.
Injection
Each mature egg is held in position while a single sperm is immobilised and drawn into an injection pipette. The needle is carefully inserted into the egg and the sperm is deposited into the cytoplasm.
Fertilisation Check
Eggs are assessed 16–18 hours after injection for signs of normal fertilisation. Successfully fertilised eggs continue to be cultured and assessed for embryo development.
Fertilisation Rates
ICSI achieves fertilisation in approximately 60–70% of injected mature eggs, compared to variable rates with conventional IVF in cases of male factor infertility.
Surgical Sperm Retrieval
For men with no sperm in the ejaculate, sperm can often be retrieved directly from the testis or epididymis using minor surgical procedures (TESA/PESA/microTESE) and used for ICSI.
Same Outcomes as IVF
Once fertilisation is achieved, ICSI embryos develop and are transferred in exactly the same way as IVF embryos. Pregnancy rates per transfer are comparable.
Safety
ICSI has an excellent safety record. Long-term studies show no meaningful difference in developmental outcomes for children born through ICSI versus conventional IVF.
Find out if ICSI is right for you
Our team includes an experienced senior clinical embryologist with specialist expertise in ICSI and advanced laboratory techniques. Book a consultation to discuss your options.
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