Marijuana and Male Fertility | SexHealthMatters.org
Jul 03, 2019
Marijuana (cannabis) use laws have been changing rapidly in North America. Last week, Illinois became the 11th U.S. state to legalize recreational marijuana, and such use became legal across Canada last October. Mexico might legalize recreational marijuana later this year.
With marijuana more freely available, people do have health concerns. In regard to sexual and reproductive health, both men and women should know the possible short-term and long-term effects of marijuana on their sexual performance and fertility.
In today’s post, we’ll discuss some recent research of interest to men and to couples who are interested in having children.
Before we get started, let’s take a moment to consider past research on marijuana and male fertility. Back in 2011, we reported on ways marijuana might affect sperm cells:
When healthy sperm cells are released, they don’t start swimming toward the egg right away. Instead, they go with the flow of the semen until they are closer to the egg. Then the swimming starts in a process called hyperactivation.
But sperm under the influence of marijuana start swimming immediately. The result? Many tire themselves out and don’t reach the egg at all.
Those that do reach the egg are less likely to fertilize it. This is because THC [tetrahydrocannabinol – marijuana’s active ingredient) hinders their ability to release enzymes needed to pass through the egg cell’s wall.
What do scientists think of marijuana’s effects on sperm now? The answers are mixed.
Increased Sperm Concentrations
In February 2019, researchers reported that men who had smoked marijuana in the past had “significantly higher concentrations of sperm” than men who had never smoked it.
Between 2000 and 2017, researchers collected and analyzed 1,143 semen samples from 662 men who were patients at a fertility clinic. The men also answered questions about their marijuana use.
Over half the men said they’d smoked marijuana at some point in the past. Forty-four percent said their smoking days were behind them, but 11% said they still smoked. About 45% of the men said they had never smoked marijuana.
Semen sample analyses showed that men with a history of smoking marijuana had an average of 62.7 million sperm cells per milliliter of semen. For men who had never smoked, the average count was 45.4 million sperm per milliliter.
The researchers also looked at how many men had sperm concentrations below 15 million per milliliter, the “normal” benchmark set forth by the World Health Organization. Five percent of marijuana smokers fell into this category, but over twice as many – 12% – of the nonsmokers did.
Does this mean that marijuana leads to higher sperm concentrations? Not necessarily. The authors pointed out that the men may have mis-stated their marijuana use, since the drug was illegal for most of the study period.
Also, the results run counter to previous studies that have shown negative effects on sperm. So more research is needed.
“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,” said study co-author Jorge Chavarro of the Harvard Chan School of Public Health 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,” he added.
Negative Effects on Sperm
Another study, published in April 2019, had some discouraging news for hopeful fathers.
At the annual meeting of the American Urological Association, researchers reported that sperm quality declined in men who used marijuana.
Their study involved 622 men between the ages of 18 and 59. One hundred twenty-five of the participants were infertile, 144 men used tobacco, and 74 men used marijuana. Another 279 fertile men who did not use tobacco or marijuana served as a comparison group.
After analyzing the men’s semen samples, the researchers found poorer semen parameters among marijuana users compared to the men who used tobacco. The marijuana users had fewer sperm cells per milliliter. Their sperm also had worse motility (ability to swim to an egg cell for fertilization) and poorer morphology (defects in size and shape).
We still have a lot to learn about marijuana’s effects on our general health, as well as our sexual health. In the meantime, couples who hope to become parents should be open about their marijuana use when talking to their doctors. They should also be up front about the use of any other substances that could reduce their chances of conceiving.
Even if you’re not thinking about having children, take a moment to consider your own marijuana use. Do you think it’s impacting your health, even in subtle ways? If so, don’t hesitate to bring this up with your doctor and take steps to get your use under control.
Simon, Darran and Nicole Chavez
“Canada just legalized recreational pot. Here’s what you need to know”
(Updated: October 17, 2018)
“Illinois becomes the 11th state to legalize recreational marijuana”
(June 25, 2019)
Harvard T.H. Chan School of Public Health
“Marijuana smoking linked with higher sperm concentrations”
(Press release. February 5, 2019)
Nassan, Feiby L., et al.
“Marijuana smoking and markers of testicular function among men from a fertility centre”
(Full-text. February 5, 2019)
Journal of Urology
Hallak, Jorge, et al.
“MP75-09 Marijuana Consumption Has a Direct Deleterious Effect on Spermatozoa by Increasing Intracellular Reactive Oxygen Species Levels 20 Times More Than Tobacco Smoking: Reasons For Concern On Widespread Use”
(Abstract. Published: April 1, 2019)
Medical News Today
Nall, Rachel, MSN, CRNA
“Normal sperm count: Everything you need to know”
(Last reviewed: March 28, 2019)
“Studies: Weed Degrades Sperm, Spurs LUTS”
(May 5, 2019)
The Motley Fool
“Mexico Aims to Legalize Recreational Marijuana Before October”
(April 28, 2019)
The Science Times
“Marijuana Use Found to Cause Infertility Among Men”
(May 6, 2019)
“Marijuana and Male Sex Health”
(May 31, 2011)