How does ICSI differ to IVF?

The world of fertility treatment can seem like a minefield, especially when you’re new to the abbreviations for words you may otherwise not have come across.

Here we consider how IVF and ICSI differ, and when ICSI would be recommended as opposed to conventional IVF.

What is IVF?

IVF places your eggs with prepared sperm in culture media within a laboratory dish. The sperm will naturally penetrate the egg leading to fertilisation overnight. The resulting embryos will develop in an incubator for three to five days. Your embryos are monitored by an embryologist and the best will be chosen for transfer to your womb.

What is ICSI?

With Intra-Cytoplasmic Sperm Injection (ICSI) a single sperm is selected by an embryologist, taken up in a fine glass needle, and injected directly into each egg. Your fertilised egg (embryo) is then transferred into your womb in the same way as an IVF cycle.

Similarities and differences of IVF and ICSI

ICSI is similar to IVF as eggs and sperm are collected from each partner or donor. On the day of egg collection, an embryologist inseminates the eggs and the following day selects out those that are fertilised. They are kept and monitored in an incubator for up to five days and the best embryos are transferred into your womb to implant.

ICSI differs from IVF as each egg is individually injected with a single sperm, bypassing the stage where the sperm has to naturally penetrate the egg.

When is ICSI used?

ICSI is used if the sperm is unlikely to fertilise an egg naturally. This may be when:

Sperm count is very low
Sperm can’t move properly
Sperm has a high rate of abnormality
Sperm is retrieved directly from the epididymis (PESA) or the testicles (TESA), from the urine, or by electro-ejaculation
There are high levels of antibodies in the semen
Previous IVF treatment has resulted in failed fertilisation
Sperm has been frozen

What ICSI offers

ICSI offers men with very few sperm (oligospermia), no sperm (azoospermia) in their semen but have had successful surgical retrieval of sperm, or high numbers of abnormal sperm that are unable to fertilise an egg, the chance of having their own genetic child with their partner.

For patients using frozen sperm, or who have had a previous failed cycle due to low fertilisation, it also offers the chance of achieving a pregnancy.

Contact us

If you’d like more information about fertility treatment at Complete Fertility Centre then please call our Admin team on 023 8120 6980 or email

2 thoughts on “How does ICSI differ to IVF?”

  1. Many people have problem knowing the difference between the both. I know this as many have asked me too for this difference between the two. I am glad that you shared this post. It’s in my bookmarks now. Will definitely recommend this article to everyone now.

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