Smoking cannabis could damage male fertility

Men who smoke cannabis could be damaging their fertility, according to new research by Queen's University Belfast.

During a multi-centre study on the lifestyle habits of infertile men, Queen's researchers noticed that many men attending for infertility investigations at Belfast's Royal Maternity Hospital were using cannabis on a regular basis. This led to the launch of a study looking at the direct effects on sperm function of THC - the active ingredient in cannabis.

The study by the Reproductive Medicine Research Group discovered that THC impedes sperm motility, making it less likely that the sperm will reach the egg to fertilise it. Researchers also found that another key function of the sperm – to digest the egg's protective coat with enzymes in a bid to aid sperm penetration – is impaired in the presence of cannabis.

Dr Sheena Lewis, from the Department of Obstetrics and Gynaecology, who leads the Reproductive Medicine Research Group, said recent reports carried out on sea urchin sperm suggest that cannabis may be a major cause of infertility by inhibiting sperm functions necessary for fertilisation.

"These experiments on human sperm tell the same story," she said.

Speaking at the annual British Fertility Society meeting in Cheltenham on 31 March, Dr Lewis said: "Following the Government's recent reclassification of cannabis from Class B to Class C, the need to determine its effects on male fertility is even greater, so that men can make an informed choice about smoking the drug based on its risks to their health."

Infertility already affects one in six couples across the United Kingdom and 40% of these cases are due to problems with sperm.

It is estimated that 3.2 million people in Britain smoke cannabis.

(MB)