Teenage girls who smoke marijuana could permanently damage their fertility, researchers warn.
A study led by the University of California, Irvine (UCI) found that adolescent female mice exposed to tetrahydrocannabinol (THC), the psychoactive chemical in the drug, had 50 percent fewer healthy ovarian follicles than the control group by the time that they were adults.
Researchers believe that the body’s endocannabinoid system – which is stimulated when marijuana is used – damages follicles or causes them to activate too quickly, causing them to become depleted.
With marijuana use now commonplace among teens across America, researchers fear that many young women are unknowingly harming their chances of having a child in the future.
While the last study was on mice, separate research has shown that pregnant women who use cannabis are at greater risk of birth defects, miscarriages and stillbirths.
Teenage girls who smoke marijuana could permanently damage their fertility, researchers warn (stock image)
Researchers found that mice exposed to THC regularly for two weeks had 50 percent fewer ovaries, including primordial ovaries that represent the number of eggs a woman will have for the rest of her life
Marijuana is legal for recreational use in 21 US states and Washington DC (orange). It is available for medicinal use in 17 states (green)
“Given that more and more teenagers and young adults are using cannabis, especially as they have easier access to the substance, the findings of this study are particularly important,” said Dr Ulrike Luderer, lead author of the study and professor of environmental health at UCI .
“It is imperative to widely communicate the impact of early childhood cannabis exposure on adult reproductive health.”
An estimated 3.3 million American teens between the ages of 12 and 17 use cannabis, experts warn.
The use of THC, the chemical in the drug that gives someone a “high” feeling, has been legalized recreationally in 21 US states and the District of Columbia.
Nearly all of these states have made the change in the time since the Covid pandemic, seeing increased tax revenue from marijuana sales as an opportunity to fill the state coffers.
Although it has often been used as a street drug, its widespread legalization has increased marijuana use among young Americans.
A study published late last year by Oregon Health & Science University found that cannabis use among American teens increased by 245 percent between 2000 and 2020.
Not much research has been done on the potential harms of widespread cannabis adoption.
However, early signs point to many long-term negative effects of taking the drug, including heart problems, cognitive problems and lower IQ.
In November, researchers found that marijuana use increased a person’s risk of developing the deadly heart disease atrial fibrillation by more than 30 percent.
Now the UCI study shows that young women in particular can put themselves at risk by using the drug.
The researchers, who published their findings in the journal Toxicological Sciences, injected mice around 30 days old with THC daily for two weeks.
These mice would be considered adolescents, as the species matures when they are about three months old.
When the mice were 70 days old, researchers checked how many primordial follicular ovaries they had.
These are ovaries in the earliest stages. They will eventually develop into eggs that a woman will ovulate.
Like mice, female humans are born with the ovaries they have throughout their lives. A lower ovarian count greatly reduces her chances of getting pregnant in the future.
They found that mice exposed to the THC had half as many ovaries as other mice of the same age.
This was true at all stages of ovarian development, meaning that the mice exposed to the drug were generally less fertile than their peers.
“Our findings provide unexpected new insights into the long-term impact of THC on reproductive function and aging,” said Dr Daniele Piomelli, study co-author and professor of anatomy and neurobiology at UCI.
“Our hope is that our findings will motivate teenage girls to make better, more informed decisions about whether or not to take cannabis products.”
This isn’t the first study to link THC use to poorer fertility.
A 2018 study found that men who smoked cannabis had lower sperm counts than their peers.