Medical

Light cannabis use may increase sperm count

Light cannabis use may increase sperm count

They found that the men in the study who used marijuana at some point in their lives had higher sperm counts and sperm concentrations than those who never used marijuana.

According to a team at the Harvard T.H. Chan School of Public Health, men who had smoked marijuana had higher sperm concentration and count than men who had never inhaled.

One widely circulated 2014 study involving almost 2,000 British men - the world's largest study to explore how common lifestyle factors influence sperm morphology (the size and shape of sperm) - found that males under 30 with less than four-per-cent normal sperm were almost twice as likely to have used cannabis in the previous three months. In addition, men in the study self-reported their marijuana use, and it's possible that some participants were not truthful about their marijuana use, due to the social stigma or illegal status of the drug in MA at the time the data was collected.

Previous studies had shown that smoking cannabis reduces sperm counts and testosterone levels. This system sends signals to the brain and these signals may play a role in fertility, they explain.

One possible explanation could be that men who generally produce higher testosterone levels are more likely to use marijuana, rather than the implication that cannabis use itself affects sperm potency.

"These unexpected findings highlight how little we know about the reproductive health effects of marijuana, and in fact of the health effects of marijuana in general", Chavarro said in a press release.

"Our results need to be interpreted with caution, and they highlight the need to further study the health effects of marijuana use".

"We spent a good two months redoing everything, making sure that there wasn't any error in the data", said Dr Jorge Chavarro of the Harvard T.H. Chan School of Public Health.




Having said that, this piece of new information is even more surprising because Bloomberg reported that men who smoke cannabis could actually have "great fertility". In fact, this group was more than twice as likely to drop below the World Health Organisation's threshold for "normal" sperm levels.

"There seems to be a lot going on in terms of legalization, but not an equally fast pace in terms of knowing what the health effects of marijuana might be", Chavarro added.

Although there are more sperm, their quality might be affected by marijuana use in ways that remain undetected.

In all, little over half of the men (55%) reported never smoking marijuana in their lifetimes, and 11 percent said they are a current user of cannabis and smoke regularly.

However, each additional year that had passed since a man last used marijuana a slight rise in sperm count would appear.

None of these limitations or considerations invalidate study's findings, it's just a sign, as Chavarro said, that we need to study cannabis more (the fact that cannabis is still considered more unsafe than opioids by the USA government remains a roadblock to that research, incidentally).

He said studies in the past that suggest drug use lowers sperm count don't specify cannabis, and are usually an amalgamation of several drugs. It may be that low or moderate levels of marijuana use have a beneficial effect on sperm production, but heavier use reverses this effect.

Whether those changes can be passed on to a child remains unknown, but for now, some researchers are warning that men in their childbearing years should consider how weed might impact their fertility and possibly their offspring.