The world has taken another tentative step closer to reversible male birth control thanks to a recent Master’s graduate from South Africa. During her studies at Stellenbosch University, Kyla Raoult demonstrated the potential of using a non-hormonal hydrogel technology to reversibly block the passage of sperm through the vas deferens.
“The hydrogel is designed to stay in place until the patient wants to restore fertility,” Raoult explained in a statement.
When injected – which Raoult says could eventually be accomplished easily and quickly in a doctor’s office – the gel is designed to form a semi-permeable barrier within the vas deferens in under a minute. Pores within the gel allow seminal fluid to pass through normally but are too small for the sperm cells themselves. While the gel is in place, any sperm produced are re-absorbed into the body, in the same way as would happen after a vasectomy.
The big difference compared with a vasectomy is that the gel could theoretically be dissolved easily to completely reverse the process.
“By simply injecting a solution into the gel to reverse the process, the chemical bonds in the gel are broken, causing it to dissolve into a watery substance that can be flushed out.”
The polymers that make up the gel have been shown to be safe for the body, and the treatment does not alter hormone levels in any way.
“This technology could help men reduce their fertility, without the usual side effects of hormone blockers, and then restore it when they’re ready to start a family,” Raoult said.
She developed the hydrogel during her Master’s studies in Polymer Science after being inspired to search for new contraceptives, since the vast majority of methods on the market are still aimed at females.
“Men’s options are mostly limited to condoms, vasectomies and some hormone-based methods. Condoms aren’t always 100 percent effective and since they are known to decrease sexual stimulation, they are often used incorrectly, if used at all,” said Raoult. “Vasectomies are excellent contraceptives, but their reversal often results in complications, and they are more of a permanent option.”
“The hormonal options are still being tested, and their effectiveness has yet to be proven. They are also often associated with negative side effects. So, there is a clear need for a reversible, non-hormonal male contraceptive.”
More research will be needed to confirm exactly how long the contraceptive effect lasts once the hydrogel is in place, and it’s not yet possible to predict when the technology could be brought to market – it’s still in the early stages of testing.
But there’s some precedent for an approach like this. One example is ADAMTM, a sperm-duct-blocking hydrogel and delivery system being developed by medical device company Contraline, which reported earlier this year that ADAMTM demonstrated 12 months of efficacy in a preliminary human trial.
Another similar treatment called RISUG® (Reversible Inhibition of Sperm Under Guidance) has attracted a lot of attention since it was developed a number of years ago. After some issues were identified in early trials, an extended phase III clinical trial began in 2003. However, the fact remains that no male birth control drug has yet been approved by the US Food and Drug Administration.
Raoult’s supervisor, Professor Bert Klumperman, has been studying the polymer used in RISUG® with the aim of improving efficacy and reversibility, and Raoult’s new work builds on this.
It’s been a very long time since a new male-targeted contraceptive was developed, a fact that can be shocking when you consider other scientific breakthroughs that have happened much more recently. There’s lots of exciting research happening, but it hasn’t yet translated to a more equitable contraceptive offering. The demand is certainly there – a recent study in Nature found that the number of vasectomy consultations and procedures increased significantly in the US in the aftermath of the Supreme Court decision that overturned Roe v Wade.
This latest work is promising too, but we will still have to wait a little longer to see reversible, non-hormonal male contraception become widely available.
