Contraceptive injection for men could end need for vasectomy

The end of the vasectomy is on the horizon after scientists announced human trials for a new contraceptive injection for men.

The simple process, which takes just a few seconds, involves injecting a harmless gel into the tube which transports the sperm to create a blockage. 

It is the same tube which is severed or tied during a vasectomy, but crucially the new process can be reversed by a second injection which quickly dissolves the gel barrier and restores fertility.

When rhesus macaques monkeys were injected and then allowed to mate freely for two years, no infants were conceived. 

Scientists at the Parsemus Foundation in California are beginning trials on men to see if the process is equally successful in humans.  There are currently no long-acting, reversible contraceptives available for men, whose only options are condoms or a vasectomy.

Dr Angela Colagross-Schouten, lead veterinarian on the macaque project said: “We were impressed that this alternative worked in every single monkey, even though this was our first time trying it."

Around 11,000 men in Britain have a vasectomy each year, a figure which has fallen considerably in recent years because men are waiting until they are older to start a family, or avoiding the procedure in case they divorce and want more children.

Genevieve Edwards, Director of Policy at Marie Stopes UK

Although vasectomies are 99 per cent effective they can lead to painful swelling as well as ongoing discomfort for men and are increasingly being rationed by Clinical Commissioning Groups to save money. 

The new injectable gel, called Vasalgel, is made from a dense web of molecules which form a viscous barrier when entering the tube connecting the testicles to the penis. 

The team behind the gel is a not-for-profit organisation so the injection is likely to be fairly cheap once it comes to market, and could eventually be offered on the NHS if is passes regulatory approval.  

British scientists said that if human trials proved effective there would be a "worldwide market" for the product, and said the initial tests showed "great promise".

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Prof Adam Balen, chairman of the British Fertility Society, said: “This is an interesting technique that achieves a reversible vasectomy by blocking the passage of sperm with a substance that later can be flushed out.

“If free of side effects then this novel approach has the potential for great promise as a male contraceptive. It is essential to know that the reversibility remains, irrespective of the duration of use.”

Allan Pacey, Professor of andrology at the University of Sheffield, said: “I would imagine there is a worldwide market for a new male contraceptive, but trials in humans and more long-term safety data are required before we will know if it is a success.”

Prof Richard Anderson,  head of section of obstetrics and gynaecology, University of Edinburgh, added: “As an 'efficacy' study showing real-world effectiveness, this is very promising, and while it was not designed to investigate complications or reversibility, these may have benefits compared to vasectomy.”

Charities also welcomed the research, but warned that only condoms could prevent sexually transmitted diseases (STIs). 

Genevieve Edwards, director of policy at Marie Stopes UK said: "At the moment, men only have the choice between one-off condoms or vasectomy if they want to prevent pregnancy, so this development is potentially very interesting.

"I'd imagine this might be popular with couples in a relationship with shared views on fertility, or men who don't currently want to risk a pregnancy but might want children in the future.

"You'd have to watch out for a return to fertility though to avoid unwanted pregnancy, and of course, condoms are the only way to prevent STIs."

The results of the primate study were published in the journal Basic and Clinical Andrology.