Chronic marijuana use alters female reproductive system, may impact successful conception


Hands in blue nitrile gloves hold tweezers to transfer medical marijuana buds to a petri dish; several Erlenmeyer flasks with liquid in them are seen in the background and foreground.

An OHSU study in nonhuman primates finds that regular use of marijuana products may increase risks of ovulatory disfunction. (Getty Images)

The use of marijuana products as often as three times per week may have profound impacts on menstrual cycles and female reproductive hormones, says a new report published online in the journal Fertility & Sterility Science.

The study, conducted at the Oregon National Primate Research Center at Oregon Health & Science University, monitored the reproductive systems of healthy female nonhuman primates following exposure to Delta-9-tetrahydrocannabinol, or THC, the main psychoactive ingredient in marijuana.

The nonhuman primates, all of reproductive age with a history of successful conception, received a THC edible once daily over the course of three months. The edible was ingested in addition to their standard diet of chow. THC dosing, based on published medical marijuana acclimation recommendations for humans, increased monthly with the largest dose reaching 2.5mg.

Close-in head shot of Jamie Lo, M.D., a smiling Asian woman with long, black hair

Jamie Lo, M.D.

“In just a short time period, we observed irregularity in the animals’ reproductive cycles,” said the study’s lead author Jamie Lo, M.D., MCR, associate professor of obstetrics and gynecology (perinatology and maternal-fetal medicine), OHSU School of Medicine, and Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center. “Overall, menstrual periods were longer in duration and levels of follicle stimulating hormone, one of the critical regulators for the body’s reproductive function, increased. These factors suggest the strong potential for reproductive system dysfunction that, in turn, may impact the ability to become pregnant.”

Not surprisingly, notes Lo, as the dose of THC increased, so did the impact to menstrual cycle length and follicle stimulating hormone levels. “While we don’t yet know why THC influences the female reproductive system, we do know that the response appears to…