Snip has lingering effects

LONDON - Vasectomies may not be as reversible as doctors had previously thought.

New research presented at a meeting of the British Fertility Society last week shows that the operation has a long-lasting effect on sperm count.

Men who have had a vasectomy, even if it has been reversed, produce less sperm and have poorer success rates when their partners have fertility treatments.

"We did not expect to see this reduction in sperm count or pregnancy due to previous vasectomy and ongoing studies are attempting to decipher the reasons for it," said Dr Carmel McVicar, of Queen's University in Belfast.

Vasectomy involves cutting and blocking the tubes through which the sperm pass into the semen. Reversing it can be difficult and it is not always successful, especially if it has been done many years earlier.

In studies at the university, Dr McVicar found that men who had had the operation produced about a third less sperm than men who had not had a vasectomy.

Their success rate after a treatment for male infertility was also about 50 per cent lower.

"In the past, a vasectomy was for life. Now men attend our clinic every week wanting to have a second family with a new partner," she told the meeting.

In a separate study presented at the meeting researchers from the university said smoking cannabis damaged male fertility by impairing the sperm's ability to fertilise the female egg.

The findings confirm early research by American scientists which suggested that THC, the active ingredient in cannabis, impedes sperm motility, or ability to swim.

"Infertility already affects one in six couples across the United Kingdom and 40 per cent of these cases are due to problems with sperm," said Dr Lyn Whann, who presented the research on vasectomy reversal.

- REUTERS