Smoking weed could affect fertility in both men and women, scientists have warned.
Evidence suggests the psychoactive ingredient in the cannabis plant— tetrahydrocannabinol (THC)—activates cannabinoid receptors in a system in the body which includes the internal reproductive organs, explained scientists who presented existing studies on potential harm caused by the drug in the Canadian Medical Association Journal.
Using weed is thought to reduce sperm count, for instance. One study involving 1,215 men found that 130 individuals who smoked marijuana more than once a week in the past three months saw a cut in production of the total sperm count of 29 percent. But the cells were still able to swim and were the same size and shape in this study.
In women, marijuana is thought to prevent or delay ovulation—where the egg is released from the ovaries. A study of 201 women found that the bodies of the 29 participants who smoked the drug in the past three months seemed to put off ovulating for between 1.7 to 3.5 days on average.
“For most couples, smoking marijuana does not affect their ability to conceive,” the authors said. But the drug could pose problems for some with existing issues. They cited a U.S. survey that didn’t find a link between struggling to conceive and smoking weed for less than once a month to every day.
“However, for couples with infertility, the changes in ovulatory function and sperm count associated with smoking marijuana could compound their difficulty with conceiving,” they wrote.
Still, the researchers emphasized studies investigating the link between human fertility and using cannabis are small, not randomized, and retrospective. That means they rely on people telling the truth about their use, which can be tricky when the drug is illegal, and means they can’t collect information including the dose and mode of use.
As well as the article, the scientists also released a Soundcloud podcast.
Other recent studies have also highlighted the potential health risks associated with using the drug. A study published in April found that people who regularly use cannabis need a 220 percent higher dose of sedatives during medical procedures.
Another piece of research from May suggested teenagers who use cannabis could be at risk of developing memory problems, while another found that teenagers who use cannabis could be at a higher risk of attempting suicide and experiencing depression.
Asked if there is a risk that as cannabis is decriminalized and legalized people will see it as safe and be less wary of the potential harms, Ian Hamilton of the Department of Health Sciences at the University of York recently told Newsweek: “There is a potential risk that these policy changes are perceived by young people and adults as signalling that cannabis is harmless.”
The challenge is to provide information about the risks that people will trust and act on, he said.