Fertility experts worry about the relationship between THC and female reproduction

With the legalization in many states of marijuana for both medicinal and recreational use, fertility specialists have become increasingly concerned about how marijuana and THC can affect female reproduction.

THC is the acronym for tetrahydrocannabinola, a crystalline compound found in the marijuana, or cannabis, plant. THC is the principal psychoactive compound of cannabis and one of over 100 cannabinoids identified on the plant. With the expansion of the cannabis industry due to legalization, you can now find THC in many forms, such as gummies, candies, food and vape pen cartridges.

It’s estimated that about 10-20% of reproductive age Americans are using marijuana or THC in some way. Beyond its recreational use, THC has many proven medicinal uses, including for nausea in cancer patients, epilepsy, and chronic pain. However, researchers are still studying whether medical marijuana can help treat a number of other conditions effectively and without other potential side effects.

THC may affect egg quality and cause irregular cycles

The human body contains receptors for cannabis compounds, called endocannabinoid receptors. Some of these receptors are located in parts of the brain, specifically the hypothalamus and the pituitary, that regulate the menstrual cycle. These receptors are also found in the uterus and ovaries, underlining the concern that fertility specialists have of the relationship between THC and female reproduction.

In both animal and human studies, researchers found that frequent use of marijuana and/or THC can disrupt the brain’s ability to communicate with the ovaries. Specifically, THC slows down the release of hormones in the brain, specifically GnRH and its downstream messengers FSH and LH. This, in turn, affects the recruitment, growth and ovulation of eggs. This slowdown translates into a 2 to 3 times increased risk of having either longer or irregular cycles. So, women who smoke marijuana or ingest THC may be 2 to 3 times more likely to have irregularity in their menstrual cycle which obviously affects the ability to predict when she is ovulating and when her fertile window is.

There may also be direct effects of THC on the egg itself. One study looked at women going through IVF who smoked marijuana for more than a year. The results found that these women produced up to 25% less eggs and these eggs had lower fertilization rates. These measurements indicate that marijuana and THC affects egg quality in some way.

We still don’t have all the answers about THC and female reproduction

Studying the effects of marijuana on the human body has been historically difficult to do because it was illegal for such a long time. Study participants were hard to recruit and reluctant to share information. We know the act of inhaling smoke, whether from tobacco or marijuana, is bad for you. But is marijuana bad because of the THC or is it bad because of the smoke? That’s a little harder to differentiate in the current research information we have.

Future research is needed to look at the direct effects of THC ingested in non-smoking forms, such as edibles, to compare to the actual harmful effects that we know the act of smoking causes. However, the short term studies that have been conducted clearly show some results that are worth noting. Specifically, THC use seems to affect a woman’s cycle and egg quality. 

The bottom line on THC and female reproduction

As with all things in life and nature, extreme use of anything is most likely harmful. Limited exposure to THC is going to be less likely to have drastic effects on the reproductive system than extreme, daily use. A woman who has had an edible or two once every few months is different from someone who is smoking or ingesting THC daily.

While THC has medicinal benefits, it doesn’t provide any benefits for reproduction to justify the potential risks that have been found in both animal and human studies. We recommend that it’s best to be cautious and avoid it altogether. 

For more information on this subject, listen to The Fertility Answers Podcast Episode 27: Marijuana and Making Babies