40–50% of infertility problems in heterosexual couples are sperm-related. Many turn to intracytoplasmic sperm injection (ICSI), the most common treatment for male infertility. Just how effective is it—and who might it not be suitable for?

How does ICSI work?

ICSI is performed as part of in vitro fertilisation (IVF), in which 50,000 sperm are set beside the egg, after which one hopefully enters the cytoplasm for fertilisation. In ICSI, a tiny needle called a micropipette injects a single sperm into the egg. Once the fertilised egg (or embryo) has grown in the lab for up to 5 days, it’s transferred to the uterus to continue developing as normal.

ICSI maximises your chance of fertilisation if you’re struggling with sperm-related infertility issues.

Is ICSI suitable for me?

Your fertility specialist may recommend ICSI if:

  • you have a low sperm count, abnormally shaped sperm, or poor sperm motility
  • your partner has undergone IVF but it didn’t work
  • your sperm needs to be collected surgically, perhaps because you’ve had a vasectomy or you have a blockage caused by disease, injury, or congenital condition, which prevents them from reaching your ejaculate
  • you’re using frozen sperm, which were stored either when your fertility was under threat or following a surgical sperm retrieval
  • you’re undergoing embryo testing for a genetic condition, and sperm sticking to the exterior of the eggs would interfere with the results.

How effective is ICSI?

The fertilisation rate of ICSI in the lab is 80–85%—in other words, about 8 in 10 of the eggs involved in the procedure will be fertilised normally. Of course, as in IVF, there are many factors affecting the success rate of pregnancy once the embryo has been inserted into the uterus, such as the woman’s age and whether she herself has any difficulties with fertility.

Is there anyone ICSI isn’t right for?

If your female partner has previously undergone IVF because of poor-quality or immature eggs but the treatment was unsuccessful, unfortunately ICSI is unlikely to help.

How safe is ICSI?

ICSI is slightly riskier than some other fertility treatments. For one thing, there’s a chance the procedure could damage the eggs during the cleaning and injection processes. There have also been a tiny number of babies born with genetic or developmental defects that have been linked to ICSI. However, these problems may instead have come from the original cause of the infertility itself, not from the treatment.

There’s also the possibility that a boy conceived through ICSI may inherit his father’s infertility problems, but we can’t know yet: the oldest boys born from ICSI are only in their teens. What we do know, though, is that genetic causes of male infertility—particularly those associated with the Y chromosome—are highly likely to be passed on. If you think this might apply to you, it’s worth undergoing genetic testing. There may be another infertility treatment available to you that presents a lesser risk of passing on your infertility problems to your son. It’s worth discussing all the implications of this possibility with your clinic’s counsellor before making a decision—there may be some you haven’t considered.

Is it worth me undergoing ICSI even if I don’t have a fertility problem?

If you don’t have a male fertility problem, the odds of your partner getting pregnant are the same regardless of whether you opt for ICSI or natural insemination. The difference, of course, is that ICSI will cost you around £5,000.

What should I do if ICSI hasn’t worked?

As with IVF, many fertility experts recommend you give it a few months after treatment before trying again. This lets you regroup and destress, and enables your body to recover from what can be quite an intensive procedure. Your doctor will let you know whether another round of ICSI is likely to succeed. If they think it’s unlikely or you don’t wish to try again, you could instead explore other options, such as adoption or sperm or egg donation.