Smoking Cannabis can Shrink the Size and Shape of Sperms: Study

Smoking cannabis affects size and shape of the sperm in young men causing infertility problems, according to a study.

The use of psychoactive drugs is known to impair physical and psychological health of individuals. A research by the University of Sheffield and Manchester discovered another reason why young men should refrain from frequent intake of cannabis. They suggest smoking a joint of cannabis has more impact on sperm morphology than other life style habits like smoking cigarettes and drinking.

Their study involved 2,249 men from 14 fertility centers around the country who were surveyed about their health conditions and use of mind altering substances. They found their sperm size and shape was smaller in summer seasons compared to the sperms produced by men who withheld sexual activity for more than six days. Experts again compared the sperm structure of 318 men that was four percent smaller in size and shape with that of normal sperms of 1,652 men.

It was observed that men whose sperm morphology was four percent smaller or in participants younger than 30 who used cannabis three months before were twice less likely to have produced normal sperm samples during summer seasons.

Past clinical trials hold that sperm quality, concentration, shape and size plays a vital role in determining reproductive health of men. If sperm are smaller, then they have high chances of perishing inside the uterus before reaching the egg for fertilization. These findings strongly urge men to give up smoking cannabis and other drugs to ward off the infertility issues.

"Our knowledge of factors that influence sperm size and shape is very limited, yet faced with a diagnosis of poor sperm morphology, many men are concerned to try and identify any factors in their lifestyle that could be causing this. It is therefore reassuring to find that there are very few identifiable risks, although our data suggests that cannabis users might be advised to stop using the drug if they are planning to try and start a family," said Allan Pacey, study author and senior Lecturer in Andrology at the University of Sheffield, in a news release.

The authors also warn that common habits like drinking alcohol and using tobacco products although does not affect sperm motility and quality, it can alter the DNA in sperm head.   

More information is available online in the journal Human Reproduction.