Marijuana May Impair Male Fertility

Men who smoke marijuana frequently have significantly less seminal fluid, a lower total sperm count and their sperm behave abnormally, all of which may affect fertility adversely, a new study in reproductive physiology at the University at Buffalo has shown.

This study is the first to assess marijuana's effects on specific swimming behavior of sperm from marijuana smokers and to compare the results with sperm from men with confirmed fertility.

Marijuana contains the cannabinoid drug THC (tetrahydrocannabinol), which is its primary psychoactive chemical, as well as other cannabinoids.

Marijuana Affects Male Sperm

Results of the study were presented at the annual meeting of the American Society of Reproductive Medicine in San Antonio.

"The bottom line is, the active ingredients in marijuana are doing something to sperm, and the numbers are in the direction toward infertility," said Lani J. Burkman, Ph.D., lead author on the study. Burkman is assistant professor of gynecology/obstetrics and urology and head of the Section on Andrology in the UB School of Medicine and Biomedical Sciences. UB's andrology laboratory also carries out sophisticated diagnosis for infertile couples.

Sperm Swimming Too Fast, Too Early

"We don't know exactly what is happening to change sperm functioning," said Burkman, "but we think it is one of two things: THC may be causing improper timing of sperm function by direct stimulation, or it may be bypassing natural inhibition mechanisms.Whatever the cause, the sperm are swimming too fast too early." This aberrant pattern has been connected to infertility in other studies, she noted.

Further research in the andrology laboratory showed that human sperm exposed to high levels of THC displayed abnormal changes in the sperm enzyme cap, called the acrosome. When researchers tested synthetic anandamide equivalents on human sperm, the normal vigorous swimming patterns were changed and the sperm showed reduced ability to attach to the egg before fertilization. Only about 10 laboratories in the U.S. perform this array of sperm function tests.

Testing for Sperm Count

In the current study, Burkman received seminal fluid from 22 confirmed marijuana smokers and subjected the samples to a variety of tests. The volunteers reported smoking marijuana approximately 14 times a week, and for an average of 5.1 years.

Control numbers were obtained from 59 fertile men who had produced a pregnancy. All men abstained from sexual activity for two days before the lab analysis.

The samples from both groups were tested for volume, sperm-count-per-unit of seminal fluid, total sperm count, percent of sperm that was moving, velocity and sperm shape.

Smokers Had Less Sperm

Results showed that both the volume of seminal fluid and the total number of sperm from marijuana smokers were significantly less than for fertile control men. Significant differences also appeared when HA and velocity, both before and after washing, were assessed, the study found.

"The sperm from marijuana smokers were moving too fast too early," said Burkman. "The timing was all wrong. These sperm will experience burnout before they reach the egg and would not be capable of fertilization."

Risky for Borderline Fertility Men

Burkman noted that many men who smoke marijuana have fathered children. "The men who are most affected likely have naturally occurring borderline fertility potential, and THC from marijuana may push them over the edge into infertility," she said.

As to the question of whether fertility potential returns when smokers stop using marijuana: Burkman said the issue hasn't been studied well enough to provide a definitive answer.

"THC remains stored in fat for a long period, so the process may be quite slow. We can't say that everything will go back to normal. Most men who have borderline fertility are unaware of that fact. It's difficult to know who is at risk. I definitely would advise anyone trying to conceive not to smoke marijuana, and that would include women as well as men."

Can Smoking Pot Lower Male Fertility? Marijuana Use May Lead To Abnormal Sperm Size And Shape For Young Men

Men, got fertility issues? Smoking marijuana may lead to poor sperm morphology, minimizing the likelihood of egg fertilization.

Marijuana use is becoming increasingly popular among youth in secondary school, particularly males. The recreational drug has also been under a lot of scrutiny amid its legalization for adult recreational use in Colorado and Washington, and medicinal use in 21 states. So, it's no surprise that more research on the drug continues to surface. 

British researchers suggest if you want to start a family, you should best lay off the schedule I substance drug. According to a study published in the journal Human Reproduction, smoking marijuana can affect male fertility by altering sperm size and shape.

"Our knowledge of factors that influence sperm size and shape is very limited, yet faced with a diagnosis of poor sperm morphology, many men are concerned to try and identify any factors in their lifestyle that could be causing this,” said Dr. Allan Pacey, lead author of the study and senior lecturer in andrology at the University of Sheffield, in the press release. 

Previous research has suggested that only sperm with good sperm morphology — normal-shaped sperm and volume of fluid — are able to pass into the woman’s body following sex to make their way to the egg and fertilize it. Sperm with an abnormal shape and size usually tend to swim less because they are not as efficient as their regular counterparts.

Lifestyle factors are suspected to affect sperm morphology, but there is not concrete evidence to validate this assumption. In an effort to examine what lifestyle factors are associated with poor sperm morphology, Pacey and his team of researchers analyzed data from a cohort of men in the UK. A total of 2,249 men from 14 fertility clinics were asked to fill out detailed questionnaires about their medical history and their lifestyle. The lifestyle factors examined included: body mass index (BMI), manual work, boxer shorts, alcohol, cigarettes, street drugs, cannabis, season, and abstinence.

The participants had previously provided a semen sample as part of infertility investigations with their partner. This sample was used by the researchers in this study. The men were asked to abstain from ejaculation for a period of three to five days. All of the information about lifestyle and health factors was self-reported, with no attempt made to confirm the accuracy of health reports, such as report of a fever or pelvic ultrasound. Events such as surgery to the testes, believed to indicate an irreversible risk, were included in the analysis if they occurred prior to the semen sample.

The findings revealed men who produced ejaculates with less than four percent normal sperm, smooth, oval-shaped heads, and no fluid droplets bigger than one half of the sperm head size were nearly twice as likely to have this occur in the summer months from June to August. In addition, participants who were younger than age 30 and used cannabis three months prior to ejaculation, also were found to have poor sperm morphology. Unlike marijuana, other lifestyle factors such as smoking cigarettes and drinking alcohol had little effect on sperm morphology.

“This research builds on our study of two years ago which looked at the risk factors associated with the number of swimming sperm (motile concentration) in men's ejaculates,” said Dr. Andrew Povey from the University of Manchester's Institute of Population Health in the press release.

Those men who produced a sample after six days' abstinence were less likely to be affected by poor sperm morphology. However, the researchers could not explain this finding and believe there is little evidence that delaying fertility treatment to make adjustments to a man’s lifestyle will improve his chances of conception. Pacey does advise, “It is therefore reassuring to find that there are very few identifiable risks, although our data suggests that cannabis users might be advised to stop using the drug if they are planning to try and start a family."

While there is no clear research that shows a direct relationship between tobacco, alcohol, or caffeine use, ReproductiveFacts.org says these substances may hurt sperm DNA quality.

Marijuana may affect fertility in young men

"If you’re a cannabis user and you’re trying for a baby ... stop."

This advice comes from Dr. Allan Pacey, senior lecturer in andrology at the University of Sheffield in the United Kingdom and lead author of a new study that suggests using marijuana could increase a man's risk of fertility problems.

The study, published in the journal Human Reproduction, looked at how a man's lifestyle affects his sperm morphology: the size and shape of sperm. Researchers collected data from 1,970 men who provided semen as part of a fertility assessment.

All of the lifestyle information was self-reported, and researchers made no attempt to confirm accuracy. Of those men, 318 produced abnormal sperm, where less than 4% of it was the correct size and shape (as defined by the World Health Organization). The remaining men's sperm had a higher percentage at a "normal" size and shape.

"Cannabis smoking was more common in those men who had sperm morphology less than 4%," Pacey said. "Cannabis affects one of the processes involved in determining size and shape. And we also know that the way cannabis is metabolized is different in fertile and infertile men."

The study found that men who had less than 4% normal sperm were typically under 30 years old, had used marijuana within three months of giving their sample and were twice as likely to have provided their sample during the summer.

Any of those factors could have influenced sperm morphology, but Pacey said "the only thing we found that was a risk that a man can do something about was cannabis."

The researchers did not set out to study cannabis; they were simply collecting data about men’s lifestyles to identify risks to fertility. They looked at a number of possibilities, including cigarettes, alcohol, recreational drug use, employment history, BMI, medical history and the type of underwear the men wore. The researchers concluded that none of these were factors.

A third of all infertility cases are linked to the male partner, according to the American Society for Reproductive Medicine (PDF). The society says marijuana is associated with impaired sperm function and should not be used by men trying to conceive.

Society President Rebecca Sokol says the study confirms previous studies that found a possible but not proven link between abnormal semen and sperm function and the use of cannabis. But she warns that the study does not have enough cases to draw definite conclusions.

"The take-home lesson of the article is that clinicians should counsel their patients on the possible relationships between lifestyle factors, abnormal semen parameters and fertility outcomes," Sokol said. "This should include a discussion that the data are often inconclusive, but the motto 'everything in moderation' is a wise approach for the couple who is planning a pregnancy."

Another paper on the health consequences of cannabis was published this week in the New England Journal of Medicine. Dr. Nora Volkow, director of the National Institute on Drug Abuse, and a team of the institute's researchers prepared a paper detailing the risks based on the strongest scientific evidence currently available. According to the paper, they wanted to dispel "the popular notion that marijuana is a harmless pleasure" and does not need to be regulated.

The paper details what the research shows are the adverse effects of recreational use, including the risks of addiction. Approximately 9% of those who try marijuana will become addicted; one in six of those who start as teenagers and 25% to 50% of those who smoke daily become addicted.

The researchers also wrote about the harmful effects of cannabis use on brain development, especially in kids and teenagers. Preliminary research shows that adolescents who are early-onset smokers are slower at tasks, have lower IQs later in life and have an increased incidence of psychotic disorders.

Other problems associated with marijuana use, according to the paper, include impaired short-term memory and motor coordination, altered judgment, effects on school performance, a higher risk of motor-vehicle accidents and higher risk of cancer and other health issues like heart disease and stroke.

"There is a widespread and growing perception among not only youth, but the public in general, that marijuana is a relatively harmless drug, and it has been difficult marshaling science to correct this perception," Volkov said. "The science of marijuana is far from settled, and this has allowed advocates of various positions to cherry-pick evidence to support their particular stance."

The review also lists some of the potential therapeutic benefits of cannabis. Conditions and symptoms that may be helped by marijuana treatment include glaucoma, chronic pain, multiple sclerosis, epilepsy, nausea, inflammation and AIDS-related anorexia and wasting syndrome, according to the report.

Volkow and her fellow researchers fear that as governments begin to modify marijuana policy toward legalization, recreational use will increase, as will a host of negative health problems.

However, Mason Tvert, communications director at the Marijuana Policy Project, says the report by the National Institute on Drug abuse researchers is not an objective review of current scientific evidence.

The Marijuana Policy Project has worked to reform marijuana policies and laws since 1995 at both the federal and state level. It lobbies for legislation that would replace marijuana prohibition in favor of legal regulation. It provided much of the staff and funding in the push to legalize and regulate marijuana for adults 21 and older in Colorado in 2012, and its goal is to pass, by 2017, at least 10 more laws that would regulate cannabis like alcohol.

"NIDA has long been criticized for prioritizing politics over science," Tvert said. "They fail to acknowledge any of the well-known research that refutes, and in some cases completely debunks, their conclusions. This more closely resembles a poorly written college essay ... than it does an objective, evidence-based journal article. Every objective study on marijuana has concluded that it poses far less harm than alcohol to the consumer and to society."