ICSI – Intracytoplasmic Sperm Injection for Male Infertility

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written by Zappelphilipp Marx•27 May 2025
Microinjection: embryologist performing ICSI – sperm being injected into an egg

The intracytoplasmic sperm injection (ICSI) is now the primary micromanipulation technique when conventional in vitro fertilisation (IVF) fails due to severe male infertility. This comprehensive guide covers everything—from indications, procedure and costs to success rates, risks and the legal framework in the UK.

What exactly is ICSI—and when is it used?

Under ICSI, a single sperm is carefully selected under the microscope and injected directly into the cytoplasm of a mature egg using a micro-pipette. It is indicated for cases such as oligo-astheno-teratozoospermia (OAT), azoospermia requiring TESE/micro-TESE, high DNA fragmentation, antisperm antibodies and repeated fertilisation failure in prior IVF cycles. Genetic screening (AZF deletions / CFTR mutations) is mandatory in severe male factor cases to prevent transmission to offspring.

Quick Comparison of Fertilisation Methods

  • ICI / IVI – Home Insemination
    Semen is placed near the cervix using a syringe or cup. Suitable for mild fertility issues or donor sperm; lowest cost and maximum privacy.
  • IUI – Intrauterine Insemination
    Washed sperm are delivered directly into the uterus via catheter. Ideal for moderate male factors, cervical issues or unexplained infertility; clinically straightforward with moderate cost.
  • IVF – In Vitro Fertilisation
    Multiple eggs are stimulated and combined with prepared sperm in the lab. Standard for tubal blockage, endometriosis or failed IUI; higher success rates but greater expense.
  • ICSI – Intracytoplasmic Sperm Injection
    A single sperm is micro-surgically injected into the egg. Precision solution for severe male infertility or TESE specimens; highest cost but best chance when sperm quality is very poor.

How much does ICSI cost in the UK?

ICSI is an add-on to an IVF cycle. In private clinics, the total cost per stimulation cycle (including medication, egg collection, ICSI procedure and embryo transfer) ranges from £5,000–8,000. The ICSI surcharge alone is typically £800–1,200.

The NHS may fund up to three full IVF/ICSI cycles for eligible patients, depending on local Clinical Commissioning Group (CCG) policies and NICE guidelines.

Additional costs: Testicular biopsy (TESE) £1,500–3,000; genetic screening £250–500; preimplantation genetic testing (PGT-A) £1,200–3,000; cryostorage £300–500 per year.

Step-by-Step Process of an ICSI Cycle

  1. Assessment & Counselling: Semen analysis, hormone profile, ultrasound, infection and genetic tests.
  2. Ovarian Stimulation: 8–12 days of gonadotrophins with frequent monitoring; low-dose protocols for PCOS risk.
  3. Egg Retrieval & Sperm Collection: 34–36 hours after hCG/GnRH trigger; TESE/micro-TESE if azoospermic.
  4. Sperm Selection: Density gradient, IMSI or PICSI techniques to minimise DNA damage.
  5. Sperm Injection: One sperm per mature MII egg using a micromanipulator.
  6. Embryo Culture & Time-Lapse Monitoring: Continuous observation to Day 5 (blastocyst). Optional PGT-A/PGT-M.
  7. Embryo Transfer or Freeze-All: Single embryo transfer to reduce multiple pregnancy risk; freeze-all and transfer in a later natural or HRT cycle if needed.
  8. Luteal Support: Progesterone (gel or pessary) until 10–12 weeks of pregnancy.
  9. β-hCG Test & Scan: Pregnancy test 12–14 days post-transfer; first ultrasound at 6–7 weeks.

Success Rates – Realistic Numbers

Fertilisation rates with ICSI are around 70–80%. Clinical pregnancy rates per transfer mirror those of IVF and depend mainly on maternal age:

  • Under 35 years: 45–55%
  • 35–37 years: 35–45%
  • 38–40 years: 25–30%
  • Over 40 years: under 15%

With additional frozen embryo transfers, the cumulative live-birth rate per stimulation cycle in women under 35 often exceeds 60%.

How to Improve Your Chances

Lifestyle: Maintain a healthy BMI, stop smoking, limit alcohol to under 5 units/week, take daily folic acid and vitamin D, and do moderate exercise.

Male Factor: Eat an antioxidant-rich diet (vitamins C/E, CoQ10, omega-3) and abstain from nicotine and anabolic steroids for three months to reduce DNA fragmentation.

Medical Adjuncts: Supplements such as DHEA and CoQ10 may help poor responders (consult your clinician; evidence is limited).

Risks & Side Effects

  • OHSS: Rare (<1%) with antagonist protocols and freeze-all strategies.
  • Multiple Pregnancy: Dependent on number of embryos transferred; single embryo transfer keeps risk under 5%.
  • Epigenetic Effects: Slightly elevated risk of imprinting disorders (<1% absolute risk).
  • Psychological Impact: Stress from cost and multiple cycles; counselling is recommended.

Legal Framework (UK)

  • The Human Fertilisation and Embryology Authority (HFEA) regulates ICSI under the Human Fertilisation and Embryology Act 1990 (as amended). Clinics must adhere to the HFEA Code of Practice, including embryo culture and transfer limits.
  • The HFEA restricts embryo transfer to a maximum of two embryos for patients under 40, and three for those over 40, to minimise multiple pregnancies.
  • UK donor-conceived children may access identifying information about their donor from age 18 under donor anonymity legislation.
  • All genetic testing and embryo research must comply with HFEA licence conditions and ethical guidelines.

Scientific Sources & Guidelines

Conclusion

Intracytoplasmic sperm injection is the most precise technique for overcoming severe male infertility in the UK. With advanced micromanipulation, robust lab protocols and single embryo transfer, ICSI can achieve up to a 55% pregnancy rate per fresh transfer in younger women. Comprehensive counselling on costs, risks and psychological support—as well as genetic advice where indicated—ensures patients can make fully informed decisions about this high-tech fertility treatment.

Frequently Asked Questions (FAQ)

In conventional IVF, eggs and sperm are simply placed together in a culture dish, and fertilisation occurs naturally. In ICSI, a single sperm is injected directly into the egg’s cytoplasm, bypassing motility or morphological issues.

Severe OAT syndrome, azoospermia with TESE/micro-TESE, high DNA fragmentation, antisperm antibodies, fertilisation failure in prior IVF or very low normal sperm count (<1 million progressive motile/ml).

Private clinics: £5,000–8,000 per stimulation cycle (ICSI surcharge £800–1,200 not covered by NHS). NHS may fund up to three cycles under NICE criteria, subject to local CCG policy.

Fertilisation of 70–80% of injected eggs.
Clinical pregnancy per transfer: 45–55% (<35 years), 35–45% (35–37 years), 25–30% (38–40 years), <15% (>40 years).
Cumulative live-birth rate with frozen transfers can exceed 60% in younger women.

About 10–30% may fail due to activation errors, immature chromatin or ooplasmic defects. Egg quality as well as sperm health affect fertilisation.

No—if viable sperm are retrieved, fertilisation and pregnancy rates match those using ejaculate sperm, provided the lab specialises in TESE processing.

Evidence is mixed. High-magnification selection (IMSI) or hyaluronic acid binding (PICSI) can reduce miscarriage rates in severe teratozoospermia or high DNA fragmentation, but improvements are not guaranteed.

For women ≥35, recurrent miscarriage or multiple failed cycles, PGT-A on aneuploidy may shorten time to pregnancy and lower miscarriage risk. Requires HFEA ethics approval.

Risk depends on the number of embryos transferred, not the fertilisation method. Single embryo transfer keeps multiple pregnancy rates under 5%.

Yes—OHSS is driven by stimulation protocols rather than fertilisation technique. Antagonist protocols, GnRH trigger and freeze-all minimise risk.

Studies suggest a slight increase (absolute risk <1%) of imprinting disorders (e.g. Beckwith-Wiedemann, Angelman), but overall risk remains very low.

Stimulation 8–12 days → retrieval Day 0 → transfer Day 5 → test at 2 weeks. Total around 4 weeks.

2–4 days of ejaculatory abstinence optimises sperm volume and motility.

BMI 18.5–24.9, quit smoking, limit alcohol (<5 units/week), omega-3 rich diet, daily folic acid (400 µg) & vitamin D, moderate exercise, stress reduction.

Three-month supplementation (CoQ10 300 mg/day, L-Carnitine 2 g/day) may improve sperm motility. Evidence moderate; consult a clinician before use.

Modern vitrification yields comparable implantation and live birth rates. Frozen transfers carry lower OHSS risk and reduced hormonal load.

Combines mild stimulation (150–225 IU/day) with single embryo transfer to reduce OHSS, multiples and cost—suitable for good prognosis patients.

If viable sperm are retrieved, fertilisation rates of 60–70% are achievable, with pregnancy rates per transfer similar to ejaculate-based ICSI.

Recommended in severe male factor: AZF deletion screening, CFTR panel, karyotype. Positive findings influence treatment choice and genetic counselling.

Fertility counsellors, online support groups (RattleStork Community), HFEA patient information line and local self-help networks.