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Can Cannabis Use Affect Fertility? What You Need to Know

It’s a well established fact that using alcohol or tobacco products has a negative effect on fertility and is potentially toxic to a developing baby.

Cannabis has become increasingly popular among young people in the height of their fertile years and is often used to help manage things like anxiety and insomnia.  Due to the high rates of use and lack of clarity around this topic, I wanted to explore where cannabis sits on this line of safe to use or not during fertility.  So let’s take a look at what research is saying.


Does cannabis affect your ability to get pregnant?

It might.

The way cannabis is absorbed and causes its influence on the body is because of the endocannabanoid system (ECS) and its receptors. These endocannabinoid receptors are found throughout the reproductive system - from the hypothalamus and pituitary gland in the brain where several key hormones are produced to the ovaries and uterus. 

Current research has suggested that cannabis use can have a negative impact on hormone production, particularly FSH and LH, which are two hormones important for ovulation.  Following this it appears that cannabis can contribute to menstrual cycle irregularities and difficulty conceiving due to increased chance of anovulation. 

Other potential risks of use include increased chance of pregnancy loss, decrease in egg quality and for those undergoing IVF, decreased number of eggs able to be collected.


What effect does it have on sperm?

Not only are endocannabinoid receptors found throughout the male reproductive system, they have been found on sperm themselves allowing for direct disruption of sperm function.

There is strong evidence that it impairs all three of the main semen parameters used to measure fertility. 

Sperm count and concentration

The average sperm count for men has decreased dramatically in the last 20 years, which is thought to contribute to rising infertility issues.  Studies have shown that marijuana directly affects count, the more it is used the lower the count.  One study even found that sperm count was reduced by 29% percent in men who smoked once a week compared to those who never smoked. 

Sperm motility

This is the ability of sperm to swim, or move, which is vital to the ability to travel into the uterus to fertilize an egg.  The rate at which sperm is able to travel has been shown to be significantly reduced in cannabis users, as well as the ability to move in a straight line.  Several studies have discovered that this is due to the increase in mitochondrial dysfunction in sperm cells which equates to a decrease in available energy for the cell. 

Sperm morphology

Morphology refers to the shape of sperm and when it is irregularly shaped, its ability to move through the cervix and fertilize an egg can be vastly compromised.  Cannabis use has been shown to dramatically effect sperm morphology causing abnormal shapes; one study in the UK found that men under 30 had less than 4% normal morphology after 3 months of cannabis use. While the impact can be high, taking a break for even a week may cause some improvement in sperm shape. 

Evidence has also  shown that it negatively affects sperm viability and fertilization capacity - in other words it may prevent sperm from even being able to fertilize an egg.

Is it safe to use during pregnancy?

Endocannabinoid receptors have been found to develop on the placenta and in the growing fetus as early as 5 weeks into pregnancy which would allow for THC to bind directly to a developing baby and their source of nourishment.

Fetal exposure to THC has been linked to several adverse outcomes including preterm birth, low birth weight, still birth, fetal growth restrictions, increased fetal or neonatal mortality and congenital malformations.  It also may have long term neurological impacts once the baby is born, in the form of delay in motor development or behavioral and learning difficulties.

Cannabis appears to be often used to help manage nausea, particularly in the first trimester – however, the first trimester is quite possibly the most vulnerable time for a fetus’s developing nervous system so it isn’t advisable.

What about during breastfeeding?

There is slightly less research about this, however what is out there is concerning.  THC  may inhibit prolactin levels, which is the hormone needed to stimulate breast milk production. It is stored in the fatty tissue in the body, which is much of what the body draws from to make breast milk.

Perhaps partially due to this it has been found in concentrations up to 7x higher in breast milk than one would find in blood levels.  Additionally, it has been shown to remain in breast milk for several days. 

THC is passed on to the nursing baby through breast milk and can attach to the endocannabinoid receptors in the growing brain which may lead to slower motor development or potential learning or mental health issues as they grow.  Other risks include lethargy, suckling issues, difficulty feeding, and slower growth.


I don’t smoke, but I use edibles and/or vape, is that okay?

It’s less about how it gets into your body and more about the effect it has in your body once there.

If you are consuming cannabis and have THC in your body, then it’s able to attach to those endocannabinoid receptors and affect your cells. 

So, is cannabis safe to use while trying to get pregnant, during pregnancy or while breastfeeding?

The short answer: No.

Though we’re only just starting to see more research on these topics, so far everything is overwhelmingly pointing towards the fact that it is not safe nor advisable to use during this time period.


This is not to say that there aren’t medicinal uses for marijuana.  It can be very effective for things like pain management, anxiety, chronic disease management and more.

However, if you are trying to optimize your health, improve your fertility and give your child the best chance of good health themselves, press pause on marijuana use for now.

If you’re ready to take that step but want to find a more fertility friendly alternative to support you in absence of cannabis, naturopathic medicine has many good options. 

Reach out to discuss how we can support you.



1. Payne KS, Mazur DJ, Hotaling JM, Pastuszak AW. Cannabis and Male Fertility: A Systematic Review. J Urol. 2019;202(4):674-681. doi:10.1097/JU.0000000000000248

2. Lo JO, Hedges JC, Girardi G. Impact of cannabinoids on pregnancy, reproductive health, and offspring outcomes. Am J Obstet Gynecol. 2022;227(4):571-581. doi:10.1016/j.ajog.2022.05.056

3. Sharif A, Bombay K, Murphy MSQ, et al. Canadian Resources on Cannabis Use and Fertility, Pregnancy, and Lactation: Scoping Review. JMIR Pediatr Parent. 2022;5(4):e37448. Published 2022 Oct 19. doi:10.2196/37448


This content is for educational and informational purposes only, and is not medical advice. 


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