According to the Federal Ministry for Family Affairs, one in ten couples in Germany between the ages of 25 and 59 are involuntarily childless. There can be many reasons why the desire to have children does not come true. One of them is the lack of motility of the sperm, which as a result cannot swim into the uterus. The low ability of sperm to move – known in technical jargon as asthenozoospermia – is one of the main reasons for reduced fertility in men.
Every tenth couple in Germany has an unfulfilled desire to have children
Researchers at the Applied Microfluidics and Bioengineering (AMB) Laboratory at Monash University in Melbourne, Australia, have now conducted a study looking at how this problem could be solved. To do this, the scientists used semen samples from three healthy men between the ages of 20 and 40, from which they collected 16 biological replicates.
They then developed a system to capture individual sperm cells in microdroplets. The sperm were then exposed to ultrasound in these drops. At the same time, the researchers filmed and examined the sperm cells under a microscope.
Australian researchers expose sperm cells to ultrasound – with encouraging results
They came to the conclusion that sonicating the cells at 800 megawatts and 40 megahertz for 20 seconds drastically improved the motility of the sperm – by up to 266 percent. In addition, the proportion of inactive sperm decreased from 36 percent to 10 percent. The ultrasound had no effect on either the DNA or the viability of the sperm cells.
“The ultrasound not only improved sperm swimming speed, but helped nearly two-thirds of lower-quality sperm achieve a higher level of motility,” said Ali Vafaie, lead author of the study, according to a university press release.
Before sonication, 36 percent of the sperm cells were categorized as non-progressive or inactive (class C). 38 percent were slowly progressive (Class B). So they don’t swim in a straight line or only in small circles to the egg. 26 percent, on the other hand, were rapidly progressive (class A), finding their way to the egg in a straight path or in large circles.
After the ultrasound treatment, only 10 percent of the sperm remained in class C. The proportion of sperm in class B increased to 42 percent, and in class A even to 48 percent.
Even small increases in sperm motility can increase pregnancy rates
“We know from clinical data that increasing sperm motility by just 10 percent increases the chance of pregnancy by eight percent,” said Vafaie.
Reza Nosrati, Director of the AMB, also emphasized: “Ultrasound technology has enormous potential to increase success rates even in the most challenging cases.”
Ultimately, higher sperm motility would give couples with an unfulfilled desire to have children the opportunity to resort to less invasive and more successful artificial insemination treatments.
“By making immobile sperm motile and making motile sperm even more motile, we can help more patients meet the minimum requirements for in vitro fertilization,” says Nosrati.
The couples are then no longer dependent on intracytoplasmic sperm injection (ICSI), which is particularly used when there are immobile sperm or too few sperm. A single sperm cell is injected into an egg cell using a fine needle.
Researchers want to test the ultrasound method on subjects with immobile sperm
The researchers now want to clarify in a further study how long and in what form the increased mobility of the sperm due to the ultrasound treatment lasts. This time the test subjects are men who are less fertile because of immobile sperm.