Is ICSI better than IVF?

Neither is inherently 'better'. ICSI is essential when sperm cannot fertilise eggs naturally (male factor infertility, surgical sperm retrieval, previous fertilisation failure). When sperm quality is normal, conventional IVF has equivalent success rates and avoids unnecessary costs and minor risks of ICSI.

Does ICSI increase chance of twins?

No, ICSI itself doesn't increase twin rates. The chance of twins depends on how many embryos are transferred, not the fertilisation method. Single embryo transfer (SET) reduces twin risk regardless of whether ICSI or conventional IVF was used.

Can you do half ICSI and half IVF?

Yes, 'split ICSI' or 'half ICSI' is an option where some eggs are fertilised conventionally and others via ICSI. This is sometimes done when there's uncertainty about sperm quality, providing a backup if conventional fertilisation fails while potentially saving some eggs from ICSI if not needed.

ICSI can fail due to: egg quality issues (eggs may not survive injection or fertilise), severe sperm DNA damage (even injected sperm may not initiate fertilisation), laboratory factors, or unexplained reasons. Fertilisation failure after ICSI occurs in about 2-3% of cycles.

ICSI is performed on eggs in the laboratory, not in your body. There's no additional discomfort for patients compared to conventional IVF. The egg retrieval procedure (which happens before ICSI) is the same for both methods.

How many sperm are needed for ICSI?

ICSI requires only one sperm per egg. Even men with very low sperm counts (a few hundred) can have successful ICSI. Surgically retrieved sperm (TESA/PESA) often provides enough for ICSI when ejaculated sperm is unavailable.

Does ICSI increase birth defects?

Some studies show slightly higher birth defect rates with ICSI, but this may be related to the underlying infertility rather than ICSI itself. The absolute risk increase is small. Most ICSI babies are perfectly healthy. Discuss specific concerns with your doctor.

How is sperm selected for ICSI?

Embryologists select sperm based on appearance (morphology) and movement (motility) under high magnification. Advanced techniques like IMSI (Intracytoplasmic Morphologically Selected Sperm Injection) use even higher magnification for selection. Sperm with normal appearance and good motility are prioritised.

Can ICSI be done with frozen eggs?

Yes, ICSI is actually required for frozen (vitrified) eggs. The freezing process hardens the outer shell (zona pellucida), making it difficult for sperm to penetrate naturally. ICSI bypasses this barrier.

What if all eggs fail to fertilise with ICSI?

Total fertilisation failure with ICSI is rare (2-3% of cycles) but can occur. Options include: rescue ICSI on unfertilised eggs (if caught early), converting to a new cycle with different approach, investigating egg or sperm factors, or considering donor gametes if indicated.

IVF vs ICSI: What's the Difference? Complete Guide 2026

If you're starting IVF, you've probably heard the term "ICSI" and wondered whether you need it. Understanding the difference between conventional IVF and ICSI (Intracytoplasmic Sperm Injection) is crucial for informed decision-making about your fertility treatment.

Both methods involve fertilising eggs outside the body, but they differ in how fertilisation occurs. Your clinic will recommend one based on your specific circumstances, particularly sperm quality and previous fertilisation history.

What is the difference between IVF and ICSI?

In conventional IVF, eggs and sperm are placed together in a dish and fertilisation happens naturally. In ICSI (Intracytoplasmic Sperm Injection), a single sperm is injected directly into each egg using a microscopic needle. ICSI is used when there are male factor infertility issues or previous fertilisation failures.

When is ICSI recommended over IVF?

ICSI is recommended for: low sperm count (under 15 million/ml), poor sperm motility (under 40% moving), abnormal sperm morphology (under 4% normal forms), previous fertilisation failure with conventional IVF, using frozen sperm, surgical sperm retrieval (TESA/PESA), or unexplained infertility after failed IVF attempts.

Is ICSI more successful than IVF?

ICSI fertilisation rates are 60-70%, similar to conventional IVF (50-70%). However, ICSI is essential when sperm cannot penetrate eggs naturally. For couples without male factor issues, conventional IVF has equivalent success rates. The choice depends on individual circumstances, not overall success rates.

What is Conventional IVF?

In conventional IVF fertilisation, eggs and sperm are placed together in a laboratory dish and left to fertilise naturally. This mimics what happens inside the body, where sperm must swim to and penetrate the egg on their own.

How Conventional IVF Works

Eggs are retrieved from the ovaries after stimulation
Each egg is placed in a dish with approximately 50,000-100,000 sperm
The dish is incubated overnight (16-20 hours)
Sperm naturally compete to penetrate the egg
Fertilisation is checked the next morning
Successfully fertilised eggs (embryos) continue developing

Best For

Conventional IVF is typically recommended when sperm parameters are normal (count, motility, and morphology within healthy ranges) and there's no history of fertilisation failure.

What is ICSI?

ICSI (Intracytoplasmic Sperm Injection) is a specialised fertilisation technique where a single sperm is selected and injected directly into each mature egg using a microscopic needle. This bypasses the natural process of sperm penetrating the egg.

How ICSI Works

Eggs are retrieved and stripped of surrounding cells
An embryologist selects a single healthy-looking sperm
The sperm is immobilised (tail broken) to prevent damage
Using micromanipulation tools, the sperm is drawn into a fine needle
The needle is inserted through the egg's outer shell (zona pellucida)
The sperm is deposited directly into the egg's cytoplasm
The egg is returned to the incubator to fertilise

Key Advantage

ICSI requires only one sperm per egg, making it possible to achieve fertilisation even with very low sperm counts or poor sperm quality.

Key Differences Explained

Aspect	Conventional IVF	ICSI
Fertilisation method	Natural (sperm penetrates egg)	Assisted (sperm injected into egg)
Sperm required	50,000-100,000 per egg	1 per egg
Technical complexity	Standard laboratory procedure	Requires micromanipulation expertise
Egg preparation	Minimal (kept with cumulus cells)	Stripped of cumulus cells
Additional cost	Included in IVF	$1,500-$3,000 extra
Fertilisation rate	50-70%	60-70%

When is ICSI Recommended?

ICSI is typically recommended when there are concerns about the sperm's ability to fertilise eggs naturally. Here are the main indications:

Male Factor Infertility

• Low sperm count (oligozoospermia): <15 million/ml
• Poor motility (asthenozoospermia): <40% moving
• Abnormal morphology (teratozoospermia): <4% normal
• High DNA fragmentation

Previous IVF History

• Failed fertilisation in previous cycle
• Low fertilisation rate (<30%)
• Unexplained infertility after IVF failure

Sperm Source

• Surgically retrieved sperm (TESA/PESA/MESA)
• Frozen/thawed sperm (reduced motility)
• Very limited sperm sample

Other Indications

• PGT (genetic testing) planned
• Limited number of eggs retrieved
• Anti-sperm antibodies present

Important Note

Some clinics perform ICSI on all cycles as standard practice. While this isn't harmful, it may not be necessary and adds cost. Discuss with your doctor whether ICSI is specifically indicated for your situation.

Success Rates Comparison

When comparing ICSI vs IVF success rates, it's important to understand what we're measuring:

Fertilisation Rate

Conventional IVF50-70% of eggs fertilise

ICSI60-70% of eggs fertilise

Pregnancy Rate

Clinical pregnancy rates are comparable between IVF and ICSI when appropriate method is used. The key factor is embryo quality, not fertilisation method.

Live Birth Rate

No significant difference in live birth rates when comparing appropriate use of each technique. Success depends on factors like age, embryo quality, and uterine receptivity.

Key Insight

ICSI doesn't improve pregnancy rates over conventional IVF when sperm quality is normal. Its advantage is enabling fertilisation when it wouldn't otherwise occur.

Cost Comparison

ICSI adds to the base cost of IVF treatment due to the specialised equipment and expertise required.

Typical ICSI Costs (USD)

USA$1,500 - $3,000

UK£1,000 - £1,500

AustraliaAUD $800 - $1,500

India/Thailand$400 - $800

* Costs are additional to base IVF cycle cost. Insurance coverage varies.

Risks and Considerations

ICSI-Specific Risks

• Egg damage: 5-10% of eggs may be damaged during injection
• No natural selection: Sperm is chosen by appearance, not ability
• Slightly higher birth defect risk: Some studies suggest marginal increase (may be related to underlying infertility)

Conventional IVF Risks

• Complete fertilisation failure: Possible if sperm cannot penetrate eggs
• Polyspermy: Multiple sperm entering one egg (abnormal)
• Lower yield: May have fewer embryos if fertilisation rate is low

Reassurance

Both ICSI and conventional IVF are safe, well-established procedures. Millions of healthy babies have been born using both methods. Your clinic will recommend the most appropriate technique based on your individual circumstances.

Making the Right Choice

The decision between IVF and ICSI should be based on:

Sperm quality — ICSI is essential for significant male factor issues
Previous cycle history — Failed fertilisation warrants ICSI
Number of eggs — Limited eggs may benefit from ICSI certainty
PGT plans — ICSI is typically required for genetic testing
Cost considerations — Conventional IVF saves money if appropriate

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Frequently Asked Questions

References

Information based on clinical guidelines from ESHRE (European Society of Human Reproduction and Embryology), ASRM (American Society for Reproductive Medicine), and published peer-reviewed research on assisted reproductive technologies. Success rates are averages and individual results vary.

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IVF vs ICSI: What's the Difference?