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."
Men, got fertility issues? Smoking marijuana may lead to poor sperm morphology, minimizing the likelihood of egg fertilization.
Can Smoking Pot Lower Male Fertility? Marijuana Use May Lead To Abnormal Sperm Size And Shape For Young Men
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.
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