Scientists test gel for male birth control
First long-term contraceptive that is non-surgical
PARIS // A gel squirted into the sperm ducts of monkeys has been effective at preventing pregnancy, a study said yesterday, offering hope of a possible non-surgical, longterm and reversible male contraceptive without the side effects of hormonal changes.
The only short- term solutions available today are condoms and withdrawal, although the latter comes at a high risk of pregnancy.
Longer term, the sole option is a vasectomy, which involves tying or cutting the sperm- conducting tubes called vas deferens.
Vasectomies can be reversed in some cases, but the procedure is technically challenging and leads to low rates of fertility.
Researchers in the United States are developing a possible alternative, dubbed Vasalgel, which has proven effective in rabbits and now in rhesus monkeys, which are more closely related and anatomically similar to humans.
Vasalgel is a polymer gel injected directly into the vas deferens, creating a blockage in the tube that transports sperm from the testes.
In an experiment at the California National Primate Research Centre, 16 adult male monkeys were treated with Vasalgel before being placed with females and monitored for up to two years – a period that covered at least one breeding season for each animal.
“Treated males have had no conceptions since Vasalgel injections,” the research team wrote in the journal Basic and Clinical Andrology.
Normally, the expected pregnancy rate among females housed with males would have been about 80 per cent.
Not yet tested in monkeys, the reversibility of the method was tested in earlier experiments with the rabbits, when the gel was successfully flushed out with solution of sodium bicarbonate.
Preparations are under way for a clinical trial with Vasalgel in humans, said the Parsemus Foundation, a non-profit organisation funding the product’s development.
The test offers hope of a long-term and reversible male contraceptive without the side effects of hormonal changes