For couples undergoing fertility treatment, the first hurdle they have to face on their treatment journey, is finding out if their sperm have fertilised their eggs. The long-awaited phone call  comes with intense anxiety as it could bring an early end to their hopes of having a baby, and sadly, the outcome of this first stage ends in disappointment for many.

Chances of failed fertilisation:

Not every egg will fertilise. In fact, the average fertilisation rate for most clinics is only 65-75% and for 5-10% of couples having IVF, no eggs will be fertilised. For those having ICSI, the failure rate can be as low as 3% but we believe this is still too high. For 30% of other couples, there will be unexpectedly low fertilisation which is also a devastating blow. Sadly, we don’t yet know what causes this failure. It could be the egg, the sperm or a combination.

At our recent webinar on fertilisation failure, Dr Sarah Martins da Silva provided compelling evidence from her recent research that the sperm is a significant cause of previously unexplained fertilisation failure. She highlighted that semen analysis can’t predict how well a sperm will fertilise an egg, so we urgently need more detailed molecular tests to add to our armoury.

Dr Martins da Silva explained how the role of sperm in fertilisation is much more complex than previously thought. Of course, half of a baby’s DNA  comes from the mother’s egg and half from the father’s sperm, so sperm delivers the vital DNA that will make their child look and act like its father. There are also crucial sperm epigenetics that provide additional signals that control how this sperm DNA acts. Dr Martins da Silva’s current research is looking at a sperm protein called PLC zeta and her team has reported how a deficiency in this protein is associated with failed fertilisation and they are now looking at solutions to overcome this problem.

On-going research is increasing our knowledge and understanding of the causes of infertility, which means fertility professionals can provide couples the answers and the treatment pathway they need to give them the best chances of becoming parents. If you missed Dr Martins da Silva’s ‘Failed Fertilisation and Sperm’ webinar, and you would like to find out more about her research, you can watch it now on demand.

We’ve heard from several world-renowned specialists as part of our male fertility webinar series and are looking forward to welcoming many more in the coming months. View our list of upcoming webinars and register now to join us.

Our webinars are designed to tackle important questions which span male health and fertility. Health professionals can register for updates and reminders, and CPD points are awarded for ARCS members.

Further reading

• Brown, S. G., Miller, M. R., Lishko, P. V., Lester, D. H., Publicover, S. J., Barratt, C., & Martins Da Silva, S. (2018). Homozygous in-frame deletion in CATSPERE in a man producing spermatozoa with loss of CatSper function and compromised fertilizing capacity. Human reproduction (Oxford, England), 33(10), 1812–1816. https://doi.org/10.1093/humrep/dey278
• Brown, S. G., Publicover, S. J., Barratt, C., & Martins da Silva, S. J. (2019). Human sperm ion channel (dys)function: implications for fertilization. Human reproduction update, 25(6), 758–776. https://doi.org/10.1093/humupd/dmz032
• Brown, S. G., Publicover, S. J., Mansell, S. A., Lishko, P. V., Williams, H. L., Ramalingam, M., Wilson, S. M., Barratt, C. L., Sutton, K. A., & Da Silva, S. M. (2016). Depolarization of sperm membrane potential is a common feature of men with subfertility and is associated with low fertilization rate at IVF. Human reproduction (Oxford, England), 31(6), 1147–1157. https://doi.org/10.1093/humrep/dew056
• Williams, H. L., Mansell, S., Alasmari, W., Brown, S. G., Wilson, S. M., Sutton, K. A., Miller, M. R., Lishko, P. V., Barratt, C. L., Publicover, S. J., & Martins da Silva, S. (2015). Specific loss of CatSper function is sufficient to compromise fertilizing capacity of human spermatozoa. Human reproduction (Oxford, England), 30(12), 2737–2746. https://doi.org/10.1093/humrep/dev243
• Yelumalai, S., Yeste, M., Jones, C., Amdani, S. N., Kashir, J., Mounce, G., Da Silva, S. J., Barratt, C. L., McVeigh, E., & Coward, K. (2015). Total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta are significantly correlated with fertilization rates after intracytoplasmic sperm injection. Fertility and sterility, 104(3), 561–8.e4. https://doi.org/10.1016/j.fertnstert.2015.05.018