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ICSI vs IVF: how do they compare?

Advice | Fertility | ICSI | IVF

All of our blog posts are written, edited, or produced by the Kind iVF Content Team. This is a collaboration between our expert writers, health editors, and the leading researchers and senior doctors at our clinics across the UK.

For many people navigating fertility challenges, deciding between IVF and ICSI can be one of the first major decisions in treatment. While the procedures share similarities, they are designed to address different causes of infertility, and understanding these distinctions can help you feel more confident and informed as you plan your next steps.

This guide explains what IVF and ICSI entail, how the two treatments compare, and the factors that may influence which option is best for you.

What is IVF?

In vitro fertilisation (IVF) is an assisted reproductive technology (ART) treatment where a woman’s eggs are combined with sperm by an embryologist in a laboratory before a resulting embryo is transferred to the uterus.

The first IVF baby was born in 1978. Since then, this fertility treatment has helped countless people overcome infertility and other barriers where natural conception hasn’t happened or other treatments have not worked.

IVF is typically recommended for:

Women with blocked or damaged fallopian tubes
Those with unexplained fertility problems
Women with ovulation difficulties
Older women who are less likely to have success with less invasive treatments
Men with low sperm counts or poor sperm morphology

What is ICSI?

Intracytoplasmic sperm injection (ICSI) is a specific procedure used within IVF treatment. It involves a single sperm being injected directly into the centre of an egg for fertilisation as opposed to traditional IVF, where thousands of sperm are placed into a petri dish with an egg and a sperm fertilises it through its own natural mechanisms.

ICSI may be recommended if:

A man’s sperm count is very low
A man’s sperm is abnormally shaped or has poor motility
Sperm needs to be surgically retrieved from the testicles
Frozen sperm is being used in treatment
You require embryo testing for a genetic condition
You have had previous unsuccessful IVF cycles due to low fertilization

IVF or ICSI: which is better?

When questioning whether ICSI is better than IVF, the answer isn’t always straightforward. Instead, it is based on multiple factors, including your personal circumstances and reproductive health. However, understanding some of the key similarities and differences between IVF and ICSI can help you determine which treatment best aligns with your needs and preferences.

The process

In both treatments, medication is used to stimulate the ovaries to develop multiple follicles (which contain the eggs) rather than just one, as would be the case in a normal menstrual cycle. Response is monitored through regular ultrasounds and sometimes blood tests. Once the follicles have reached the optimal size, a trigger injection is done at a precise time to encourage the final maturation of the eggs and prepare them for egg collection.

Egg collection occurs under sedation and is a short procedure where a fine needle is passed through the vaginal wall into each ovary, and the fluid in each follicle (where the eggs are held) is drawn out.

It is at this point that the treatments differ. In standard IVF, once the viable, mature eggs have been determined, each one is placed in a petri dish, and thousands of sperm are added to the dish as well. Sperm will reach the egg using their own movement and penetrate the egg’s outer layer by releasing enzymes.

However, in ICSI, the most normal and active sperm are individually selected and drawn up into a very fine glass needle. A single sperm is then directly injected into each egg to fertilise it.

After this, both treatments are again the same. The eggs are closely monitored to see if they successfully fertilise and how they develop. After 3-5 days, the best embryo (or more rarely, two embryos) is transferred to the womb in a short, minimally invasive procedure, during which you remain awake. A fertility specialist uses ultrasound imaging to guide a fine catheter containing the embryo into the vagina, through the cervix and into the womb before carefully placing the embryo.

Any remaining embryos can be frozen for use in subsequent cycles. Approximately two weeks after egg transfer, a pregnancy test is conducted to determine if treatment was successful.

Read more about what to expect during ICSI treatment.

Fertilisation rates

The fertilisation rates of IVF and ICSI can vary depending on factors influencing the treatment, but are often comparable.

In couples where sperm parameters are normal, research suggests that standard IVF can yield improved blastocyst rates and quality. However, when sperm quality is poor, ICSI can result in better fertilisation rates. One study found that in instances of severe teratozoospermia (abnormally shaped sperm), ICSI resulted in a mean fertilisation rate of 62.7% compared to conventional IVF, which had a fertilisation rate of 44.6%.

Research has also been conducted on whether ICSI can be beneficial in instances where there are female-factor fertility issues. In a study that assessed ICSI as a treatment for women over 40 with diminished ovarian reserve, conventional IVF resulted in a 26.3% fertilisation rate, whereas ICSI had a 22.5% fertilisation rate.

Cost

The cost of fertility treatment can vary significantly between clinics if you do not meet NHS eligibility criteria for IVF and are paying privately. However, in most cases, ICSI is more expensive than IVF. This is because it is a very specialised process that is more labour-intensive than IVF and requires not only precise micro-manipulation equipment but also the expertise of a highly skilled embryologist.

At Kind iVF, we understand the financial implications of treatment. That’s why we offer treatment packages for both IVF and ICSI. Our all-inclusive IVF package is £2950, and our ICSI package is £4,400. These packages include:

Pre-treatment screening blood tests
Stimulation medication
Monitoring scans
HFEA treatment fees
A counselling session
Egg collection and sedation
Time-lapse imaging of developing embryos
Luteal support medication up to the pregnancy test date
BHCG pregnancy blood test
Pregnancy scan (at 6-7 weeks)

Use of donor eggs or sperm

Donor eggs or sperm can be used in both IVF and ICSI treatment. Donor eggs and sperm are rigorously tested, and only the highest quality sperm and eggs are approved, meaning using them can be highly beneficial if previous IVF cycles have been unsuccessful or you have known male factor infertility.

Thanks to our partnership with London Sperm Bank, Kind iVF offers donor sperm IVF to heterosexual couples, same-sex female couples and single women. London Sperm Bank can provide four different sperm sample types, including those specifically for use in IVF and ICSI.

Learn more about IVF with donor sperm.

Risks

Generally, fertility treatment is very safe, with most people no more likely to experience problems than if they had conceived naturally. However, there are some risks that it is important to be aware of when comparing IVF vs ICSI.

Possible risks of IVF include:

Ovarian hyperstimulation syndrome (OHSS): This is a condition where the ovaries become enlarged, and fluid builds up in the abdomen. Most cases are mild, but in some instances, it can be life-threatening.
Ectopic pregnancy: where an embryo implants outside the uterus, most commonly in a fallopian tube. The embryo cannot survive, and medical treatment is necessary.
Pelvic infection: In very rare cases, pelvic infection can occur after egg collection due to bacteria being introduced from the vagina into the pelvic cavity.
Multiple births: This is becoming less common as most clinics practice single embryo transfers, but multiple births can occur if two or more embryos are transferred or if a single embryo splits.

Possible risks of ICSI include:

Damage to the egg: The process of injecting the sperm into the egg can result in damage, and around 10% of eggs do not survive this process.
Ectopic pregnancy: This can occur in pregnancies after ICSI treatment, too.
OHSS: This risk comes from ovarian stimulation, which is why it can occur in the IVF and ICSI process.
Pelvic infection: As egg collection also occurs in ICSI, pelvic infection is still a risk, albeit a very small one.

Does ICSI improve IVF success?

ICSI can improve the likelihood of a live birth, but this does depend on the circumstances. By directly injecting a single sperm into an egg, ICSI can overcome male fertility issues like low sperm count, poor motility, or abnormally shaped sperm, significantly increasing the chances of fertilisation. However, for couples without these issues, traditional IVF is often just as effective.

As success rates for ICSI tend to be very similar to conventional IVF, the Human Fertilisation and Embryology Authority (HFEA) does not publish separate statistics. Overall, the number of babies born from IVF increased from approximately 8,700 in 2000 to 20,7000 in 2023 and now represents 3.1% of all births in the UK.

There has been some research conducted on live birth rates in IVF vs ICSI. One study, which compared standard IVF with normal semen parameters with ICSI where they were known male factors, found that there was a 63.5% live birth rate following IVF cycles and a 47.5% live birth rate following ICSI cycles.

What are the chances of ICSI working the first time?

ICSI and IVF success rates are impacted by many factors, with female age being one of the most influential.

According to research, live birth rates per ICSI cycle are:

34.6% for women aged under 35
25% for women aged 35-29
11.6% for women aged over 40

Data from the HFEA from 2022 reveals birth rates using fresh embryo transfers following IVF were:

35% for women aged 18-34
26% for women aged 35-37
18% for women aged 38-39
10% for women aged 40-42
5% for women aged 43-44

IVF and ICSI with Kind iVF

Kind iVF offers affordable fertility treatments, including IVF and ICSI. Our services are designed to be efficient and streamlined without any compromise on the quality of your care or the expertise of our specialists.

Our eligibility is based on just three criteria: A BMI of 30 or less, starting treatment medication before your 37^th birthday and having a good ovarian reserve. If Kind iVF isn’t right for you, we work in collaboration with London Women’s Clinic, who offer additional fertility services and treatment plans for more complex fertility cases.

We are here to support you through every stage of your journey to parenthood. If you have any questions, you can contact us or read through our FAQs. Or, if you are ready to take the first step in our patient pathway, you can book a consultation.

References

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