The world’s largest study into sperm quality and lifestyle has revealed that cannabis use doubles the risk of infertility, particularly among males under the age of 30.
Researchers have found that the consumption of alcohol and cigarette smoking does not appear to affect the shape and size of male sperm. However, cannabis has an effect on the shape of the sperm in younger men.
A specialist in male fertility at the University of Sheffield, Allan Pacey, said that males who are trying for a baby should stop smoking cannabis, however the effects will not be visible overnight. It takes about three months for sperm to be produced and this is the period of time that should be allowed to notice an improvement.
The effect on sperm production of cannabis is not known. Dr Pacey said that the association is not visible in males over the age of 30 and this is suggestive of a link to exposure to cannabis.
He said that the risk in males under 30 was doubled and this effect has not been seen in such a robust manner previously. The fact that it is prevalent among younger men indicates that it is linked to dosage as younger men may be more tempted to smoke higher quantities than older men.
The study did a computer-based analysis of ejaculates which had been collected from 318 men who had attended 14 clinics in the UK with their partners. A different team interviewed the males regarding their lifestyle, including their drinking, drug and smoking habits.
Previous studies of sperm count looked at males who often wore tight underwear. The results indicated that these men had greatly lowered sperm counts as high temperatures and body heat retention affects sperm production.
The new study looked at the shape and size of sperm as this affects their mobility. Sperm with low mobility will not go beyond the cervix of the womb and this will prevent fertilisation of the egg after sex.
The study did not find a link between the quality of sperm and factors such as tight underwear, drinking, smoking, a history of mumps, or obesity. The only factors linked to poor sperm production were frequent ejaculation, summer-time ejaculation and cannabis.
Dr Pacey stated that the knowledge of what influences the shape and size of sperm is extremely limited and many men faced with this problem are concerned about the identification of lifestyle habits that may be causing this problem. The low number of identifiable risks has provided reassurance.
The ejaculates were assessed based on the sperm quality definition provided by the World Health Organisation. It states that sperm quality may be considered as normal if more than 4% of the sperm present in an ejaculate is the correct size and shape.
Other research has discovered that a man’s sperm quality may be affected by exposure to lead and paint strippers.
Image Credit: Wiros