Teenage girls who smoke marijuana can cause permanent harm to themselves fertilityresearchers warn.

Research under the leadership of the University CaliforniaIrvine (UCI), found that adolescent female mice exposed to tetrahydrocannabinol (THC), the psychoactive chemical in the drug, had 50 percent fewer healthy ovarian follicles than controls when they became adults.

Researchers believe that the body’s endocannabinoid system, which is stimulated by marijuana use, damages the follicles or causes them to activate too quickly, exhausting them.

As marijuana use has become common among teenagers across America, researchers fear that many young women are unknowingly harming their chances of having a child in the future.

While the most recent study was on mice, a separate study found that pregnant women using cannabis are at greater risk of birth defects, miscarriages, and stillbirths.

The researchers found that mice regularly exposed to THC for two weeks had 50 percent fewer ovaries, including primordial ovaries, which 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 (orange). It is available for medical use in 17 states (green)

“Given that more and more teenagers and young adults are using cannabis, especially with easy 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.

“The effects of early-life cannabis exposure on reproductive health in adulthood need to be widely publicized.”

Experts warn that about 3.3 million American teenagers between the ages of 12 and 17 use cannabis.

The recreational use of THC, a chemical in the drug that gives someone a “high” feeling, has been legalized in 21 US states and the District of Columbia.

Almost all of these states have made changes since the Covid pandemic, seeing increased tax revenue from the sale of marijuana as an opportunity to replenish state coffers.

Although marijuana was already widely used as a street drug, the widespread legalization of marijuana has increased its use among young Americans.

A study published late last year The Oregon Health and Science University found that cannabis use among American teenagers increased by 245 percent from 2000 to 2020.

There is little research into the potential harm of widespread cannabis use.

Early signs point to many long-term negative effects from using the drug, though, including heart problems, cognitive questions and a lower IQ.

In November, researchers found that marijuana use increases a person’s risk the development of a fatal heart condition atrial fibrillation by more than 30 percent.

Now, UCI research shows that young women, in particular, may be putting themselves at risk by using the drug.

Researchers who have published their results in the Journal of Toxicological Sciencesinjected mice about 30 days old with THC daily for two weeks.

These mice could be considered juveniles, as the species reaches adulthood at around three months of age.

When the mice reached 70 days of age, the researchers checked how many primordial ovarian follicles they had.

These are the ovaries in their earliest stages. Eventually, they will turn into eggs, in which the woman will ovulate.

Like mice, human females are born with ovaries that they carry throughout their lives. Lower ovarian levels greatly reduce her chances of becoming pregnant in the future.

They found that mice exposed to THC had half as many ovaries as other age-matched mice.

This occurred at all stages of ovarian development, meaning that the drug-treated mice were generally less fertile than their peers.

“Our findings provide unexpected new insight into the long-term effects of THC on reproductive function and aging,” said Dr. Daniele Piomeli, study co-author and professor of anatomy and neurobiology at UCI.

“We hope our findings will motivate teenage girls to make better and more informed decisions about whether to use cannabis products.”

This is not the first study to link THC use to impaired fertility.

A 2018 study found that men who smoked cannabis had less sperm than their peers.