EXPERT REACTION: New ultrasound technique could boost sperm movement by 266%

This paper is of great interest as it describes a non-invasive method for enhancing the motility of individual sperm using ultrasound. The results are particularly impressive, showing the most substantial improvement in motility among the least motile sperm.

Nonetheless, it is crucial not to overestimate the technique's utility. A sperm sample is considered normal if it meets several criteria: a concentration of 15 million per millilitre, progressive motility in at least 35% of the sample, and normal morphology (structural appearance) in at least 4% of the sample.

Meeting these criteria, a sample is suitable for conventional In Vitro Fertilisation (IVF), where eggs and sperm are placed in a dish and incubated, typically overnight. The underlying assumption is that the 'best' sperm will 'win the race' and fertilise an egg, leading to a viable embryo.

However, if a sperm sample is deemed abnormal, due to issues with count, motility, morphology, or a combination thereof, the only remaining option for achieving fertilisation and a viable embryo is Intracytoplasmic Sperm Injection (ICSI). This technique, which addresses male-factor infertility by selecting and injecting a single 'best-looking' sperm into an egg, is widely utilised when sperm samples are abnormal. It typically results in normal fertilisation and the creation of high-quality embryos.

The current paper describes a technique that improves motility exclusively, and it does so at the individual sperm cell level. Therefore, it is unclear whether a similar technique of stimulating the entire sperm sample with ultrasound waves would enhance the overall motility of the said sample. If it does, the technique may enable some couples who require ICSI for fertilisation to opt for conventional IVF instead. This could reduce the costs of IVF treatment and might potentially yield more and higher-quality embryos, thereby improving the overall success rate of IVF treatments.

This novel approach could be particularly beneficial in situations where only a few poor-quality sperm are available or when no sperm can be detected in an ejaculate, necessitating a testicular biopsy to obtain sperm.

As the authors rightly point out, in such cases, a motile sperm is greatly preferred over an immotile one due to better fertilisation rates, leading to more high-quality embryos and, consequently, higher overall pregnancy rates.

Applying ultrasound stimulation to individual sperm in a sample could enhance their motility.

However, whether this improvement translates into better fertilisation rates remains to be seen, as the sperm undergoes no fundamental change; it is merely "awakened" from its slumber.

Future research should focus on clinical outcomes, such as fertilisation, blastulation, and pregnancy rates, to ascertain the clinical utility of this innovative technique.

This research by the Monash University Engineering team brings new hope to men with severe defects in sperm quality. The novel approach using ultrasound stimulation allows the movement of sperm to be enhanced by more than 250%. This opens up new treatment choices in particular for men who produce sperm that do not exhibit the usual swimming motion. In these men, it is difficult to distinguish between dead and immotile (non-moving) sperm. The new non-invasive technique that preserves sperm DNA integrity and viability provides IVF specialists with a better way to select healthy sperm. Improving sperm movement may also lead to better fertilisation and embryo development rates and ultimately to more babies born but this needs to be confirmed in further clinical studies.

Where people are having difficulty conceiving a child because of low sperm motility, this discovery could clearly be of benefit. Like any novel treatment, it would be important to be sure it is safe, and that the benefit is proven in practice. If we don’t know exactly why some sperm move less, for example, then just increasing their motility might not help with overall fertility. The process needs to be understood, and patients will need to be able to make an informed choice.

This fascinating study points to a beneficial effect on sound energy on sperm function. 

This has the potential to improve sperm function in the IVF laboratory setting so as to generate better fertilization rates, embryo development and ultimately successful pregnancy.

Clearly there now needs to be extensive safety testing in animal model studies then in establishing the effect of sonic exposure on human sperm function. 

This approach may represent a means to improve male infertility outcomes in ART (Assisted Reproductive Technologies). We at Monash IVF are excited to be working with the Monash University team in these ongoing studies.

This is a fascinating idea that requires further evaluation before being applied clinically. Further studies are needed to see if this boost in sperm movement increases the probability of normal fertilisation and a higher chance of having a healthy baby.

My first comment is that the ultrasound seems to result in a significant improvement in sperm motility. This technology would be useful for men with severe oligospermia and poor sperm motility and assist embryologists in selecting sperm to inject into eggs in IVF patients undergoing intracytoplasmic sperm injection. It would potentially be useful in couples who require surgical sperm retrieval to harvest sperm as part of an IVF treatment cycle. The sperm retrieved from testicular samples at best is only twitching and any device or application to increase sperm motility, and sperm selection and possibly enhance the outcome is enthusiastically monitored.

The authors reported that through the use of ultrasound, sperm motility increased significantly and this may assist in the sperm that is used for inseminating eggs in couples undergoing IVF treatment. My only concern is the study does not address how long the motility lasts for after the ultrasound has been applied. When eggs are inseminated with sperm as part of IVF treatment they need to remain motile for extended periods of time to fertilise the eggs. We don’t know and cannot assume this technology would improve outcomes with standard IVF.

The study does not address how long the motility lasts for and therefore more research is required in this area before that assumption can be made.

Overall, the study is very interesting it has some great results, however, further research will still be required to ultimately find its ideal application in assisted conception.