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Cannabis and Male Fertility: A Systematic Review

Purpose: With cannabis consumption on the rise and use prominent among males of reproductive age it is essential to understand the potential impact of cannabis on male fertility. We reviewed the literature regarding the effects of cannabis on male fertility.

Materials and methods: We performed a literature search using PubMed®/MEDLINE® to identify relevant studies of the effects of cannabis on male fertility. Relevant studies were identified and reviewed.

Results: The strongest evidence of cannabis induced alterations in male fertility is in the category of semen parameters. Research supports a role for cannabis in reducing sperm count and concentration, inducing abnormalities in sperm morphology, reducing sperm motility and viability, and inhibiting capacitation and fertilizing capacity. Animal models demonstrate a role for cannabis in testicular atrophy, and reduced libido and sexual function but to our knowledge these results have not yet been replicated in human studies. Studies of hormonal changes suggest inconclusive effects on testosterone levels, lowered luteinizing hormone levels and unchanged follicle-stimulating hormone levels.

Conclusions: Current research suggests that cannabis may negatively impact male fertility. Further studies are needed to validate that robust findings in animal models will carry over into human experience. Clinicians should be aware of these potential effects when prescribing medical marijuana therapies to men of reproductive age, and they should consider the degree of cannabis use as a possible component of a complete male infertility workup.

Keywords: cannabis; erectile dysfunction; infertility; male; spermatozoa; testis.

SPH Study: Marijuana Use Does Not Lower Chances of Getting Pregnant

BU SPH study surveyed more than 4,000 women in the US and Canada

Photo by iStock/MStudioImages

Marijuana use—by either men or women—does not appear to lower a couple’s chances of getting pregnant, according to a new study led by Boston University School of Public Health researchers.

The study, published in the Journal of Epidemiology and Community Health (JECH), was the first to evaluate the link between fecundability—the average per-cycle probability of conception—and marijuana use.

About 15 percent of couples experience infertility. Infertility costs the US healthcare system more than $5 billion per year, and thus identifying modifiable risk factors for infertility, including recreational drug use, is of public health importance. Marijuana is one of the most widely used recreational drugs among individuals of reproductive age. Previous studies have examined the effects of marijuana use on reproductive hormones and semen quality, with conflicting results.

“Given the increasing number of states legalizing recreational marijuana across the nation, we thought it was an opportune time to investigate the association between marijuana use and fertility,” says lead author Lauren Wise, BU professor of epidemiology.

In Pregnancy Study Online (PRESTO), a web-based prospective cohort study of North American couples, the researchers surveyed 4,194 women aged 21 to 45 living in the United States or Canada. The study specifically targeted women in stable relationships who were not using contraception or fertility treatment. Female participants were given the option to invite their male partners to participate; 1,125 of their male partners enrolled.

The researchers found that during the period from 2013 through 2017, approximately 12 percent of female participants and 14 percent of male participants reported marijuana use in the two months before completing the baseline survey. After 12 cycles of follow-up, conception probabilities were similar among couples that used marijuana and those that did not.

The researchers stressed that questions about the effects of marijuana use remain. As one example, they said, classifying people correctly according to the amount of marijuana used, especially when relying on self-reported data, is challenging. “Future studies with day-specific data on marijuana use might better be able to distinguish acute from chronic effects of marijuana use, and evaluate whether effects depend on other factors,” they wrote.

Other coauthors from BU School of Public Health include: Amelia Wesselink, a doctoral student in epidemiology; Elizabeth Hatch, professor of epidemiology; and Kenneth Rothman, professor of epidemiology; and from the School of Medicine: Shruthi Mahalingaiah, assistant professor of epidemiology and of obstetrics & gynecology. Coauthors from Aarhus University Hospital in Denmark were Ellen Mikkelsen, senior researcher, and Henrik Toft Sørensen, head of the clinical epidemiology department.

Weed Seed: Avena sterilis (Sterile oat)

Secondary Noxious, Class 3 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.


Worldwide: Native to southern Europe and the Mediterranean region; associated with the cultivation of oats (CABI 2016 Footnote 2 ; USDA -ARS 2016 Footnote 3 ). Widely introduced elsewhere and present on all continents except Antarctica (CABI 2016 Footnote 2 ; USDA -ARS 2016 Footnote 3 ). Occurs in the United States, in: CA , CO , NJ , OH , OR , PA (Kartesz 2011 Footnote 4 , USDA -NRCS 2016 Footnote 5 ).

Duration of life cycle

Seed or fruit type

Pair of florets

Identification features

  • The first floret length: 10.0 – 27.0 mm
  • The first floret width: 2.5 – 4.0 mm
  • The second floret length: 10.0 – 14.0 mm
  • The second floret width: 2.0 – 2.5 mm
  • Caryopsis length: 10.0 mm
  • Caryopsis width: 2.0 – 2.5 mm


  • Floret elongate, tapers at top into long, papery lemma extensions

Surface Texture

  • Floret pebbled texture
  • Long, stiff reddish hairs around base of the floret
  • The lemma tends to have sparse hairs, but can be removed during processing


  • Florets tend to be reddish colour with straw yellow tips, but can be solid straw yellow

Other Features

  • Florets usually shed as a pair, but may detach during processing
  • Callus at base of the first floret is prominent and elongated, the callus of the second floret is peg-like
  • A strongly bent and twisted awn is attached to upper half of lemma; up to 80.0 mm long

Habitat and Crop Association

Cultivated fields, roadsides and disturbed ground. A serious weed of arable crops, particularly cereals, with a life cycle that mirrors many annual crops. Often occurs on heavier soils, sometimes replacing the similar species A. fatua in this soil type where the two co-occur (CABI 2016 Footnote 2 ).

General Information

Like wild oat, sterile oat has been dispersed around the world as a contaminant in cereal grain and seed, as well as on agricultural equipment, straw, hay, livestock and wool. A crop mimic in Avena sp. (oat) crops, it produces seeds that are difficult to separate from grain (CABI 2016 Footnote 2 ).

Individual plants can produce up to 200 seeds, although the average in a natural population has been reported as 13-21 seeds per plant; seeds remain viable for up to 5 years in the soil (CABI 2016 Footnote 2 ).