According to Wikipedia, Marijuana usage in 2015 saw almost half of the population of the United States had tried it at some stage. 12% had used it in the past year, and 7.3% had used it in the past month. In 2014, daily marijuana use amongst US college students had reached its highest level since records began in 1980, rising from 3.5% in 2007 to 5.9% in 2014 and had surpassed daily cigarette use.
Let’s just think about that for a moment. Marijuana use in US students exceeds cigarette smoking, and 6% get stoned every day! The rise in use is probably a function of more relaxed attitudes to marijuana, formal research into its medicinal potential, and increasing legalisation in many US states.
Now this might be a cue for some people to start waxing on about how things have changed, and the differences in societal attitudes to marijuana compared to the 1970s. But if you think of the French phrase ‘Plus ça change, plus c’est la même chose.’ This translates as ‘The more things change, the more they stay the same.’ So all that has really happened here is that we have substituted or are beginning to substitute one stimulant for another.
Whether this is ultimately a good thing or not for western society is yet to be determined. Although the current indicators suggest that marijuana consumption is probably ultimately less harmful than either tobacco or alcohol use, but there is nothing to suggest that people won’t indulge in all three now they have the legal option to do so!
What can be said about the effect of marijuana and its increasing use on fertility and the ability to conceive and bear children?
The detrimental effects of smoking and excessive drinking including their effects on fertility are well documented. That is because these substances have been around for a very long time.
However, the effects of newer substances such as new drugs and environmental chemicals on fertility will only be known in the space of a generation. This might be as long as 20 years and legislation never waits that long.
For instance, marijuana was legalised in Canada in October of last year. According to Professor Sarah Kimmins, a researcher in male fertility at McGill University in Montreal, multiple issues related to infertility appear to increasingly involve men and marijuana use may be a contributing factor.
Professor Kimmins says, “I think there’s enough evidence now where you can say, ‘Listen, marijuana is bad for your sperm’. The consensus for people working in fertility and in andrology is that the effects of marijuana are primarily negative in terms of sperm health and fertility. So we know use of marijuana recreationally is associated with about a 30% reduction in sperm number and also a decline in sperm function.”
Indeed, a 2015 study of 1,200 Danish men found a 28% reduction in the sperm concentration in those who used marijuana more than once a week.
For female users the picture is less clear, yet marijuana has been shown to have an effect on ovulation patterns. This is because THC the active ingredient in marijuana acts on the body’s endocannabinoid system, which is part of the reproductive tissues of both men and women.
With this in mind the Canadian Medical Association Journal (CMAJ) has recently issued a four point advisory note regarding marijuana use and fertility:
- Tetrahydrocannabinol acts on the endocannabinoid system, which is ubiquitous in reproductive tissues
- Marijuana use can decrease sperm count
- Marijuana use may delay or inhibit ovulation
- For most couples, smoking marijuana does not affect their ability to conceive, but for couples with subfertility or infertility, it could be a contributing factor.
The last point is poignant; couples that are having difficulty conceiving should probably avoid using marijuana as they consider other lifestyle changes toward good health. As one of the writers of the CMAJ advisory note goes on to say, “If someone already has some underlying fertility problem, if you’re then also reducing the amount of sperm available or changing when the egg is being released that could further impact your ability to get pregnant.”
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