Intracytoplasmic Sperm Injection (ICSI)

Intracytoplasmic Sperm Injection (ICSI) is a specialised form of IVF that can greatly improve fertilisation in cases of severe male infertility. In this article, we’ll briefly explain what ICSI is, outline the situations in which it’s most beneficial, walk through the procedure step by step, and discuss success rates in the UK. We’ll also explore common risks or abnormalities, break down typical treatment costs, and address frequently asked questions to help you feel confident about your fertility journey.

Understanding Intracytoplasmic Sperm Injection (ICSI)

Intracytoplasmic sperm injection (ICSI) is a type of assisted reproductive technology (ART) that involves the direct injection of a single sperm into the centre of an egg (oocyte) (Haddad et al., 2022). Originally developed to address severe male infertility, ICSI has quickly become the most widely used insemination method worldwide, with 66.5% of fertility centres reporting the use of ICSI over traditional IVF (Haddad et al., 2022). By bypassing many of the natural barriers that sperm encounter—such as the egg’s surrounding layers—ICSI promotes fertilization for couples who might otherwise have difficulty conceiving.

Who Can Benefit from ICSI Treatment?

While ICSI is a viable treatment within ART, there are certain cases where the method particularly relevant; male infertility cases, severe or unexplained fertility issues, as well as fertility preservation and other special cases.

Male Infertility Cases	Severe or Unexplained Fertility Issues	Fertility Preservation and Other Special Cases
Low Sperm Count (Oligozoospermia): A single, viable sperm can be injected directly into the egg.	Unsuccessful Traditional IVF: ICSI is recommended when fertilisation rates remain low in standard IVF.	Using Frozen Sperm: Ideal for limited or previously cryopreserved samples.
Poor Sperm Motility or Morphology: ICSI bypasses motility or structural defects by placing sperm exactly where fertilisation occurs.	Genetic or Structural Concerns: Direct sperm injection helps if a chromosomal abnormality or defect is suspected (Esteves et al., 2022).	Pre-Treatment Preservation: Cancer patients who freeze sperm before chemotherapy often benefit from ICSI to achieve fertilisation later.
Obstructive Azoospermia: Men missing the tubes that carry sperm (e.g., absence of the vas deferens) can undergo surgical sperm retrieval, followed by ICSI.	Egg-Specific Factors: ICSI can overcome a tough or abnormally thick egg membrane (zona pellucida).	Older Maternal Age / Poor Oocyte Yield: When fewer eggs are retrieved, ICSI maximises each egg’s chances for fertilisation.

Even couples with no clear cause of infertility often benefit from ICSI, especially if they’ve experienced total fertilisation failure in standard IVF. Studies show children born from ICSI remain statistically healthy (Haddad et al., 2022), although a small number may inherit paternal genetic factors. For many, a single cycle of ICSI can significantly improve the chance of a successful pregnancy compared to traditional IVF alone.

The ICSI Procedure: Step-by-Step Details

ICSI has become a standard fertility treatment—especially for severe male infertility—because it significantly increases fertilisation rates when sperm parameters (count, motility, or morphology) are low. Below is a step-by-step look at how an ICSI cycle typically works.

Step 1 – Ovarian Stimulation

Goal: Stimulate the ovaries to produce multiple eggs (oocytes), rather than the single egg released in a typical menstrual cycle.
Medications: Gonadotropins (e.g., FSH) and GnRH agonists or antagonists are used to control and boost follicle development.
Monitoring: Ultrasound scans and hormone tests track follicle growth. Once the follicles reach the right size, an hCG injection triggers final egg maturation.

Step 2 – Egg (Oocyte) Retrieval

Procedure: Typically done 34–36 hours after the hCG trigger. A fine needle guided by ultrasound is inserted vaginally to collect fluid from the ovarian follicles.
Outcome: The fluid is examined under a microscope to locate the cumulus–oocyte complexes (COCs).
Assessment: Mature eggs (in metaphase II) are identified and set aside for ICSI. Immature eggs (germinal vesicle or metaphase I) may continue maturing in the lab, though they’re less likely to be used immediately.

Step 3 – Sperm Collection and Preparation

Fresh or Frozen: Most centres do ICSI with fresh ejaculated sperm if available; in other cases, you’re using frozen sperm or surgically retrieved sperm (e.g., PESA, MESA, TESE) for men with obstructive azoospermia (such as bilateral absence of the vas deferens).
Quality Checks: Sperm are assessed for motility and morphology. Even with a very low sperm count (oligozoospermia), a small number of viable cells can often be found.
Preparation: Technicians isolate the healthiest sperm, sometimes using density gradients or other lab techniques.

Step 4 – Injecting the Sperm Directly Into the Egg

Micromanipulation Setup: Under a high-powered inverted microscope, an embryologist uses two micropipettes—one to hold the egg in place and another to inject the sperm.
Sperm Immobilisation: The sperm’s tail is gently “stunned” or immobilised in a drop of specialized medium (e.g., containing polyvinylpyrrolidone).
ICSI Injection: A single sperm is drawn into the fine injection pipette tail-first and inserted through the zona pellucida (outer egg shell) and into the ooplasm (egg cytoplasm).

Step 5 – Fertilisation Check and Embryo Development

Fertilisation Assessment: About 16–20 hours post-injection, lab staff check for the presence of pronuclei (indicating normal fertilisation).
Embryo Culture: Successfully fertilised eggs (now embryos) are grown in culture media, typically for two to five days.
Embryo Evaluation: Embryologists grade embryos based on cell division, appearance, and overall quality. Embryos that reach the blastocyst stage (day five) may offer higher implantation rates.

Step 6 – Embryo Transfer and Follow-Up

Embryo Transfer: One or more embryos are transferred to the uterus. Elective single embryo transfer is increasingly recommended to lower the risk of multiples.
Pregnancy Test: A blood test (beta-hCG) is performed about two weeks later to confirm whether implantation and pregnancy occurred.
Further Monitoring: Prenatal care includes ultrasounds to track healthy fetal growth. Couples are also advised of possible risks associated with IVF and ICSI, including a slightly increased chance of chromosomal abnormalities.

ICSI Success Rates in the UK

UK data typically report IVF and ICSI success rates together, a large observational study by Bahadur et al. (2020) examined 319,105 IVF/ICSI cycles in the UK from 2012 to 2016. Within this combined group:

Overall Live Birth Rate (LBR): Around 25% to 27% per cycle over that five-year period.
Trends Over Time: The success rate for IVF/ICSI slightly increased from about 25% in 2012 to around 27% in 2016.

While these figures do not isolate ICSI from standard IVF, many clinics report that ICSI success—particularly where male infertility is the main factor—can be similar to or slightly higher than traditional IVF in couples who qualify for ICSI. Variations depend on factors such as maternal age, ovarian stimulation protocols, and the underlying cause of infertility.

Possible Abnormalities and Risks Associated with ICSI

Although ICSI dramatically boosts fertilisation rates in couples with male factor infertility, it is still an invasive procedure under the umbrella of assisted reproductive technology (ART). Some of potential risks and abnormalities, which are largely overlapping with standard IVF, include:

Multiple Pregnancy (Twins and Triplets): About 13% of IVF/ICSI births in the UK from 2012 to 2016 involved multiple gestations. Note that these rates can be reduced through elective single embryo transfer (eSET).
Ovarian Hyperstimulation Syndrome (OHSS): OHSS can occur from the medications used to stimulate egg production. Although moderate to severe OHSS was documented in IVF/ICSI cycles (about 0.25% per cycle), it remains relatively uncommon but potentially serious.
Chromosomal Abnormalities and Birth Defects: Large-scale studies suggest the overall risk of major congenital malformations after IVF/ICSI is slightly higher than in the general population, often cited around 3–4%
Procedure-Related Factors: Because ICSI involves direct sperm injection into the centre of the egg, embryologist expertise and proper laboratory conditions are crucial to minimise egg damage or fertilisation errors.
Potential Long-Term Implications: ICSI may “bypasses” natural sperm selection processes, possibly allowing certain sperm defects (including those at the genetic level) to be passed on. For instance, a small number of children may inherit their father’s Y-chromosome microdeletions if that was the underlying cause of infertility.

Despite these risks, ICSI is considered safe. Most children born from ICSI are still healthy, and ongoing research continues to refine safety protocols.

Costs of ICSI Treatment in the UK

Cost considerations are central to choosing the right fertility treatment. While data frequently combine IVF and ICSI in cost analyses, the average fee for a single IVF/ICSI cycle in the UK (not including medication and additional “add-on” procedures) often ranges between £3,500 and £5,000. In 2016, the mean tariff was ~£4,699 per IVF/ICSI cycle. Key points regarding expenses include:

Upfront Clinic Fees: Base package typically covers consultations, monitoring, egg collection, and lab fees. Frozen sperm use may add storage costs.
Medication: Ovarian stimulation drugs typically add around £500–£2,000, depending on the protocol.
Add-Ons: Optional treatments (e.g., genetic screening, embryo “glue”) can raise costs further, though their benefits vary.
Multiple Cycles: Repeated attempts, if needed, escalate the total expense.
NHS Funding: Approximately 40–45% of IVF/ICSI cycles receive NHS funding, but eligibility and coverage differ across regions.
Maternal & Neonatal Costs: Multiple births may require extra care, increasing NHS expenses, especially for twins or triplets.

Taking the Next Step in Your Fertility Journey

Ready to start your family? Our dedicated team at Ovoria is here to guide you through every aspect of ICSI—helping you understand your options, navigate costs, and work closely with our UK clinic partners. Get in touch today to schedule a consultation and take a confident step toward growing your family.

Contact

Is ICSI Better Than IVF?

They’re equally effective overall, but ICSI is often recommended if sperm factors (like low count or poor motility) are the main concern. Standard IVF may suffice for unexplained infertility or when sperm parameters are normal.

When Was ICSI First Used?

ICSI was first introduced in the early 1990s as a breakthrough option for couples facing severe male infertility.

How Many Vials of Sperm Are Needed for ICSI?

Typically, one vial of sperm is enough—because ICSI injects a single sperm cell directly into each egg, only a small number of viable sperm cells are needed.

References

Haddad, M., Stewart, J., Xie, P., Cheung, S., Trout, A., Keating, D., Parrella, A., Lawrence, S., Rosenwaks, Z., & Palermo, G. D. (2020). Thoughts on the popularity of ICSI. Journal of Assisted Reproduction and Genetics, 38(1), 101–123. https://doi.org/10.1007/s10815-020-01987-0

Devroey, P. & Van Steirteghem, A. (2004). A review of ten years experience of ICSI. Human Reproduction Update, 10(1), 19–28. https://doi.org/10.1093/humupd/dmh004

Bahadur, G., Homburg, R., Bosmans, J. E., Huirne, J. a. F., Hinstridge, P., Jayaprakasan, K., Racich, P., Alam, R., Karapanos, I., Illahibuccus, A., Al-Habib, A., & Jauniaux, E. (2020). Observational retrospective study of UK national success, risks and costs for 319,105 IVF/ICSI and 30,669 IUI treatment cycles. BMJ Open, 10(3), e034566. https://doi.org/10.1136/bmjopen-2019-034566

Intracytoplasmic Sperm Injection (ICSI) – The Procedure, Success Rates, and Costs