Scientists believe they have developed a technique which will allow ultrasound to be used as a male contraceptive.
Preliminary results from a study at the University of North Carolina have shown that when therapeutic pressure is used in rats, sperm production was halted temporarily, with no long-term effects on health or fertility.
The team, lead by Dr. James Tsuruta, has theorised that if men receive pressure from an ultrasound to the testes for ten to 15 minutes, then they could be protected from unwanted pregnancy for up to 6 months.
They have said that they hope that equipment already found in sports medicine clinics for treatment of conditions such as scar tissue which has developed after a breakage could be used to provide a long-term, reversible and inexpensive contraceptive.
The ultrasound seems to disable the sperm cells, reducing the supply of stem cells which ordinarily replenish sperm reserves. It is unclear why the effects last for 6 months, when usually stem cells take 2 months to develop into functioning sperm. It could be that the testes automatically make the stem cells divide and multiply when sperm is low, rather than develop into sperm cells. It is also possible that the ‘nurse cells’ involved in sperm production are affected by the ultrasound.
The research team has been awarded a grant worth $100,000 from the Bill and Melinda Gates Foundation, which invests very heavily in research into sexual health and contraception, to continue with the development of the treatment.
They will be trying to discover the lowest intensity of ultrasound needed to stop sperm production before starting trials on humans.