Swimmers at Risk

Marijuana is good for many things but, as it turns out, maintaining fertility isn’t one of them. Researchers have noticed that marijuana use is common among men presenting for fertility evaluation and may have a detrimental effect on semen quality, particularly morphology and volume. Confusingly, though, it may also be protective against abnormal sperm motility. So what are we to believe? In a bid to find out, a daring evaluation took a closer look at this at-risk population by assessing the semen of 409 current, past, and “never-users” (1).

Compared with never-users, current and past users had a significantly higher likelihood of abnormal sperm strict morphology (33.1 percent versus 50.7 and 53.4 percent, respectively). However, sperm motility was more likely to be below average in never-users than in current and past-users (38.3 percent versus 21.1 and 27.2 percent). Upon analyses, current use was associated with increased odds of abnormal strict morphology and semen volume less than WHO reference value, whereas below-average sperm motility was reduced.

We asked lead author Omer Raheem, Assistant Professor of Urology at Tulane University School of Medicine, USA, if he was surprised there wasn’t a bigger difference between current and past users. “One would expect and hope that past smokers would have better sperm morphology since discontinuation of marijuana smoking; however, it remains unknown how long it takes to recover sperm morphology after discontinuation of marijuana smoking.”

Interestingly, despite most sperm parameters’ being affected by marijuana use (potentially signaling the negative impact of spermatogenesis and testicular function overall), Raheem would not advise men against cannabis if they want a child – but he does offer a word of caution.

“Although marijuana use can be helpful in some medical conditions, such as chronic pain, it has a negative impact on men’s reproductive ability and may render them infertile for a long time. Having said this, given the paucity of quality data investigating the full effect of marijuana on men’s health, a larger study is urgently needed to evaluate these findings.” So now you know. Stay safe out there, guys.