Marijuana may damage semen quality and affect male fertility, new research suggests.
Researchers looked at samples from men in Washington, where the drug has been legal for recreational use since 2012, and compared it with their cannabis consumption.
They found that men who had consumed cannabis in their lifetime were more likely to have abnormally-shaped sperm and lower concentrations of sperm compared to men who had never used the drug.
Lead researcher Omer Raheem, who presented his paper today at the American Society for Reproductive Medicine conference in Denver, said these findings show doctors should warn men trying to conceive that marijuana may play a role in slowing that process down.
Sperm quality and counts are plummeting across the US and worldwide, and no one can pinpoint the driving force.
Since it’s likely the result of multiple factors, including chemical exposures and poor diet, researchers are exploring all areas to find ways to curb the drop.
Cannabis, too, is a booming but under-studied area that has scientists both excited and skeptical. The drug is now legal in more than half of the United States for medical use, and nine for recreational use. And yet, science is still racing to catch up with legalization, and the true benefits and down sides are still coming to light.
Inspired by a paper in Denmark which found cannabis affected male fertility, Dr Omer Raheem, a urologist now at Tulane University, wanted to see if the same was true in America, in a state where marijuana is now part of the culture, especially for men under 45.
His team prospectively evaluated semen analyses from 409 men who’d been assessed for infertility.
Before sending their samples to be screened at the lab, the men were given a health assessment form to fill out, which included questions about their marijuana consumption, as well as tobacco consumption, age, and race.
Dr Raheem’s team then cross-referenced their answers with their lab results.
About half of the men (174, or 43 percent) had consumed marijuana in their lifetime. Many of them (103, or 25 percent) said they did not use the drug any more, and the rest (71, or 18 percent) defined as ‘current users’.
Regardless, those who had ever used the drug had poorer semen quality than those who hadn’t.
The team saw damage on all fronts – decreased volume, morphology (the shape), and total progressive motile count (how many sperm can actually move).
Men who had smoked marijuana also had higher risks of abnormally shaped sperm, which can hamper its attempts to enter an egg.
‘Doctors need to be aware of the negative effect and counsel their patients about the negative effects,’ Dr Raheem told DailyMail.com.
‘Marijuana has been legalized in nine states, particularly in the West Coast, but there are negative effects.
‘We need to do more studies to understand these negative effects.’