Reversible Sperm Inhibition

Reversible inhibition of sperm under guidance (or RISUG for short) is a reversible vasectomy-like procedure currently being developed in India. RISUG, which was formerly referred to as SMA, involves injecting a gel into the vas deferens (the tubes which transport sperm cells from the testicles during ejaculation) which kills off the sperm cells as they pass through the tube. Clinical trials on RISUG are underway at the Indian Institutes of Technology, in Delhi, under the leadership of Dr. Sujoy K. Guha. Although trials have thus far been successful and reassuring, the RISUG procedure has not yet been approved for use by doctors in India, and studies in the UK have yet to begin.

The RISUG Procedure

A gel composed of styrene maleic anhydride (SMA) and dimethyl sulfoxide (DMSO) is injected via the scrotum into the vas deferens. This gels coats the walls of the vas deferens but instead of blocking the tube, as in a vasectomy, the chemical composition of the gel renders sperm unable to travel and unable to fertilise an egg. Researchers are not yet certain why this happens. One theory is that the gel changes the natural pH environment inside the vas deferens. Doctor Guha has said that the combination of positive and negative charges on the surface of the gel cause the sperm membranes to burst, leaving the sperm cells ineffective. The injection itself can be administered through the skin of the scrotum without making any cuts, if the doctor is able find the vas deferens through the skin. Alternatively the non-scalpel method associated with the vasectomy procedure may be used. Here, a tiny puncture is made in the skin of the scrotum and a small pair of forceps is used to open up the hole. The surgeon uses this very small hole to find the correct place in the vas deferens into which to inject the gel. The procedure usually lasts for fewer than 15 minutes.

Comparisons With Vasectomy

Just like the vasectomy, the RISUG procedure is carried out as outpatient procedure and the patient can generally go home on the same day. Unlike the vasectomy, the RISUG procedure is a non-surgical or semi-surgical procedure and may be performed without making any cuts in the skin. This takes away the need for stitches and reduces recovery time. The only side effect of RISUG reported from studies is some slight swelling of the scrotum which goes down after a few weeks. Unlike the vasectomy, which takes two to three months to become fully effective, RISUG is effective almost immediately. Participants in trials were advised to use condoms for 10 days after the procedure, but even those men who did not do so didn’t get their partners pregnant within that time. Indeed, of the 250 men who have taken part in trials over the years, only one reported that his partner became pregnant after the procedure. In his case, the RISUG injection had been incorrectly administered. Perhaps the most important advantage of RISUG when compared with the vasectomy is that the procedure is easily reversible, whereas only 50 % of vasectomy reversals are successful.

RISUG Reversal

RISUG can be reversed using another injection of DMSO, which flushes out the gel inside the vas deferens. Vibration, a low electric current and some per rectal massage may be required to completely remove the gel. So far, the reversal procedure has only been carried out on primates, however, each reversal has been successful. A study in 2005 found that sperm returns to its normal, healthy state within 150 days of the reversal procedure. The RISUG can be reversed within months or years of the procedure having been carried out. If no reversal is carried out, the RISUG may be reliable method of birth control for at least 10 years.

RISUG Advantages

Proponents of the RISUG procedure state that it has the following advantages as a form of birth control:

Wide ranging suitability – because it is easily reversible, the procedure is suitable for young and older men alike, whether or not they have already had children.

Effectiveness – as previously mentioned, only one unplanned pregnancy has occurred throughout the course of the entire study and this was caused by an incorrectly administered injection.

Convenience – RISUG takes away the need to interrupt sex and put on a condom, or for a woman to remember to take a birth control pill every day.

Non-invasive – the RISUG is less invasive than the vasectomy procedure. It has fewer side effects and a shorter recovery time.

Reversible – the patient can change his mind at any point after the procedure and have it reversed.

Further Research

Trials are on-going in India but have yet to even begin in the UK. Researchers say that unless the public makes its desire known for such a birth control solution for men, the funds for researching RISUG in the UK are unlikely to be made available.

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