96 percent of vasectomy patients cleared without need for multiple semen samples

Research from The Netherlands, published in the June issue of the urology journal BJUI, showed that 51 per cent of the 1,073 samples contained no sperm and a further 45 per cent contained less than 100,000 immotile sperm. No paternity was reported in the cleared group after a follow-up of at least a year.

"Vasectomy is a minimally invasive surgical procedure that provides a widespread, reliable and relatively easy method of birth control" says co-author Dr Herman van Roijen from the Department of Urology at St Elisabeth Hospital, Tilburg, The Netherlands.

"One of the major drawbacks is that a considerable number of men still have a few immotile sperm in their semen for a year or more. Conventional guidelines have stated that clearance can only be given to men who provide one or two sperm-free samples. The fear of legal action if pregnancy does occur has led to very conservative vasectomy protocols.

"However, our study -- based on guidelines issued by the Dutch Urological Association -- shows that one semen test is adequate to provide clearance in the vast majority of cases."

A two-step process was developed by the research team to analyse the semen samples.

• The first step was wet slide analysis of the semen samples in a deep chamber to provide a relatively reliable indication of sperm numbers and motility. This showed that 51.2 per cent of the samples were sperm free and 41.5 per cent contained less than 50 immotile sperm, giving an initial clearance rate of 92.7 per cent.
• The remaining 7.3 per cent were then tested using a Neubauer Haemocytometer, according to guidelines issued by the World Health Organization. This resulted in a further 3.3 per cent being cleared and four per cent being declared potentially fertile.

A total of 481 men (44.7 per cent) received clearance with residual immotile sperm still present in their semen. After a follow-up of at least one year, no pregnancies had been reported.

"Our study clearly shows that three months after vasectomy about half of our patients were still producing sperm, albeit immotile and in very small numbers" says Dr van Roijen. "In fact, we found even higher percentages than previous studies.

"However, our study also showed that these residual sperm are of no clinical consequence."

The authors conclude that the era of repeated visits to a clinic to deliver yet another semen sample many months after a vasectomy may now be over.

"If the guidelines now being employed in The Netherlands were adopted elsewhere, it could dramatically increase the number of men who could be cleared three months after a vasectomy, having provided just one semen sample" says Dr van Roijen.