In the autumn of 1977, Lesley Brown, a young woman from Oldham, had a procedure to collect a single egg. The egg was placed in a dish and the sperm of her husband added, which swarmed around egg the within seconds. The egg fertilised and was transferred back to Lesley. Nine months later, she gave birth to her daughter, Louise Brown, the first IVF baby.

The fancy term for mixing eggs and sperm together in a lab, is in-vitro fertilisation (IVF). IVF was developed for women like Lesley who couldn’t conceive due to blocked Fallopian tubes. Since the first IVF baby, a lot has changed and IVF is now used to treat many causes of infertility, including ovulation problems, endometriosis and when doctors can’t figure out why there is a problem.

IVF: Sperm are mixed with eggs in a dish and left alone to fertilise.
ICSI: A single sperm is injected into each egg.

One drawback with IVF is that it doesn’t work as well when men have a poor sperm count. In these cases, when the eggs and sperm are mixed together, occasionally fertilisation does not occur. Nobody quite understands why.

Twenty years later, scientists discovered that this problem could be overcome by injecting each egg with a single sperm, a procedure called intracytoplasmic sperm injection (ICSI).

Today, confusion often arises between the two procedures. The image of a needle inside an egg is what comes to mind for most people when they think of IVF–but this is actually ICSI. A Google image search for IVF more often than not shows ICSI being performed rather than IVF.

Couples having treatment will not notice the difference between IVF and ICSI, because ovarian stimulation, egg collection and embryo transfer are the same for IVF and ICSI. The only difference is what is done in the lab.

What is better: IVF or ICSI?

Fertilisation rates between the two techniques are the same when done for the right reason. When the sperm tests are normal, there is absolutely no reason to do ICSI.

Some of the reasons for doing ICSI are:

  • poor sperm quality (abnormal motility and morphology)
  • sperm has been retrieved surgically
  • previously failed fertilisation with IVF
  • using of frozen eggs

Rates of miscarriage or abnormalities in babies born are no different between the two techniques. Some studies have shown men conceived by ICSI may have lower sperm counts than other men. However, this is probably due to the reasons for performing ICSI rather than the procedure itself. Furthermore, many men conceived by ICSI have better fertility than their fathers.

If you are paying for treatment, ICSI usually costs around £1000 more than IVF.

The bottom line

IVF is mixing, ICSI is injecting. Unless there is a good reason to do ICSI–IVF is better.


Matt is an NHS Consultant in Newcastle with over ten years of experience. His PhD research into subfertility and miscarriage involved developing a clinical trial and patient engagement.