Gel alternative to vasectomy works in monkeys, offers hope for male contraceptive

A gel squirted into the sperm ducts of monkeys has been effective at preventing pregnancy, said a study on February 7, 2017 which offered hope of a solution for men reluctant to go under the knife for family planning.

A gel squirted into the sperm ducts of monkeys has been effective at preventing pregnancy, said a study Tuesday which offered hope of a solution for men reluctant to go under the knife for family planning.

While several birth control options exist for women, the race is on for a non-surgical, long-term and reversible male contraceptive without the side effects of hormonal changes.

The only short-term solutions available today are condoms, which many people complain interfere with sex, and withdrawal before ejaculation, which comes with 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. This prevents sperm from mixing with seminal fluid ejaculated during sex.

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 also in rhesus monkeys - 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 out through the penis.

In an experiment at the California National Primate Research Center, 16 adult male monkeys were treated. They were housed with females, and monitored for up to two years - covering at least one breeding season per 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.

"The presence of Vasalgel appears to be well tolerated and placement resulted in minimal complications," the researchers wrote.

One monkey of the 16 had symptoms of sperm granuloma, a buildup in the vas deferens which is a common complication in about 60 per cent of human vasectomies, they added.

Not yet tested in monkeys, the reversibility of the method was tested in earlier experiments in rabbits, when the gel was successfully flushed out with solution of sodium bicarbonate.

Preparations are underway for a clinical trial with Vasalgel in humans, said the Parsemus Foundation, a non-profit organisation funding the product's development.

The research has benefits for the monkeys as well, researchers added.

It is ideal to house captive rhesus monkeys in groups for their social welfare, but populations can quickly explode due to high fertility.

And vasectomy in monkeys is more complex than in humans, with many complications.

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

Top 5 STIs in Singapore

  • With each intimate relationship, we bring with us a sexual history, and there are numerous other sexually transmitted infections out there other than HIV.
  • Here are the top five reasons why you should always insist on using a condom.
  • Chlamydial infection can cause painful urination, as well as urethral discharge in men and vaginal discharge in women.
  • Untreated cases may lead to infertility and pregnancy-related complications in women.
  • It can also infect the rectum, causing painful defecation and rectal discharge.
  • Most people infected with this STI experience no symptoms, so they may unknowingly pass it to their partners.
  • Genital warts are caused by the human papillomavirus (HPV). A number of strains of HPV specifically cause it.
  • Those who do will notice cauliflower-shaped growths appearing on the genitals and sometimes around the anus (even without anal intercourse). - See more at:
  • This is another bacterial infection, other than chlamydia, that can cause infertility.
  • Victims may experience a burning sensation when urinating or notice a creamy white, yellow or green penile, vaginal or anal discharge.
  • The throat can also be infected through oral sex. The infection can also spread through the bloodstream and infect other parts of the body, including the joint and skin.
  • Get Tested: To detect the presence of this infection, swabs are taken from suspected areas, or urine samples are collected.
  • A person can be carrying the herpes simplex virus (HSV) even if he hasn't been humping around.
  • HSV can cause either genital or oral herpes, the latter more commonly known as cold sores.
  • Herpes is contracted through direct skin-to-skin contact with an infected individual via sexual intercourse or kissing.
  • The signs, if they appear, include painful urination, and sores on the genitals, anus, thighs and buttocks (ouch!).
  • In severe outbreaks, there may also be flu-like symptoms, fever and muscle ache.
  • This can be deadly if left untreated.
  • In the early stages, an infected person may notice a painless sore in the genital region, or a widespread rash that tends to affect the palms and soles.
  • Syphilis is spread through direct contact with a syphilitic sore, which is found mainly on the genitals, anal regions, and (less commonly) around the lips and mouth.
  • Get Tested: It can be diagnosed with a blood test or a swab taken from the sore.