31st March 2004

Scientists call for more research into the long-term effects of vasectomy, as results revealed today1 suggest that the effects of ‘the snip’ might not be as “reversible” as previously thought.

Work done at Queen’s University Belfast on testicular biopsies shows that men who had a vasectomy more than 10 years ago have a much lower sperm count than non-vasectomized fertile men, and that ICSI pregnancy success rates using sperm from these men were more than 50% lower.

Researchers from Reproductive Medicine2 tested 21 men who had vasectomies for contraception after having children. They found that their sperm count was about three times lower than that of the 39 non-vasectomised fertile men assessed, at 3.6 million sperm per gram of biopsy tissue compared to 11.2 sperm per gram.

Analysing the biopsies they discovered that the number of Sertoli cells – which nourish the sperm through their development in the testis – was normal in the vasectomised individuals. However, the numbers of developing sperm (spermatids) were significantly reduced.

More alarmingly, they found that couples undergoing fertility treatment where the male had been vasectomised (and reversal had failed) were less than half as likely to get pregnant as couples with other infertility problems. However, only 17 couples post-vasectomy and 37 other infertile couples have been assessed in this part of the research. A larger multicentre study is required to elucidate these findings.

Dr Carmel McVicar, who presents the work today, said ‘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.’

‘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. Men who are considering vasectomy certainly need to think very carefully about the long-term consequences to their future fertility.’

Notes for Editors
1The effects of obstruction on spermatogenesis is presented at The Annual British Fertility Society Meeting 2004 on Wednesday 31st March 2004, in Cheltenham, UK

2CM McVicar*, DA O’Neill#, N McClure*, SJ McCullough#, LH Dalzell* & SEM Lewis* from *School of Medicine, Obs & Gyn, and #Anatomy, Queen’s University Belfast, Belfast, Northern Ireland, UK
The British Fertility Society is a national multidisciplinary organisation representing professionals practising in the field of reproductive medicine. www.fertility.org.uk