Does Marijuana Affect Fertility?

When it comes to cannabis and trying to conceive, you may want to pass the dutchie altogether. From the damage of smoking and vaping to the studied effects of THC and CBD on egg and sperm health, implantation, hormones, pregnancy and more, there are many reasons to abstain. Here, we dive into the research to look at how weed impacts fertility.

Does smoking and/or vaping cause infertility?

Before we get into the ingredients themselves, let’s talk about the method of consumption. Most experts agree that smoking anything isn’t great for our reproductive health (or our health in general). That’s because the combustion of the substance creates toxins that cause oxidative stress, which negatively impacts sperm and egg health.

Vaping might seem like a cleaner option, but there’s no consensus that it is a safer option at this point. Though a 2019 study indicated that cannabis vapor contains significantly fewer toxins than smoke, there’s still the question of what else is in it. In fact, additives to THC-containing vapes or e-cigarettes are thought to be harmful agents.

Because we know that the number-one factor that affects egg and sperm quality is oxidative stress, for now, the recommendation is to not smoke or vape anything while TTC. So does that mean that edibles and oils are OK? Let’s break down the effects of the actual THC/CBD on preconception and pregnancy.

Does weed cause female infertility?

Whether it’s ingested as an edible/oil or inhaled from a joint/vape, THC (the main psychoactive in cannabis) absorbs quickly into the bloodstream and spreads throughout the body. This includes the uterus, fallopian tubes and anterior pituitary, which all have endocannabinoid receptors.

A 2021 review highlighted the various ways that marijuana can hurt your odds when trying to conceive:

• Ovulation: Occasional cannabis use was associated with extending the follicular phase by 3.5 days—that means it takes you longer to ovulate, which of course is key for conception. And when it comes to regular cannabis use, it was associated with more anovulatory cycles (where you don’t ovulate at all) in a six-month period than those who weren’t using cannabis at all.
• Implantation: The study’s authors theorize that THC may negatively affect implantation. This is based on the finding that THC can suppress the release of LH (luteinizing hormone) post-ovulation, which may reduce progesterone production.
• Time to conceive: Studies in this area have been mixed, but a recent study looked at people who were trying to conceive after experiencing pregnancy loss and found that cannabis users were 41 percent less likely than non-users to conceive each cycle. In the six-month period, 42 percent of the cannabis users became pregnant compared to 66 percent of the non-users.
• IVF: We’ve seen mixed findings from these studies as well. A 2019 study suggested a higher rate of pregnancy loss in cannabis users, however a larger 2021 study showed no decrease in implantation rate or increase in miscarriage rate between users and non-users.

Does weed affect sperm?

You’ll also find endocannabinoid receptors throughout the male reproductive system: in sperm, the testicles, seminal vesicles (where sperm is produced), erectile tissue, and in the central nervous system which is involved in arousal, sexual function and sexual behaviour.

A 2019 systematic review looked at cannabis use and sperm parameters and highlighted areas of concern as well as some mixed results:

• Sperm count and concentration: A decrease in both the total number of sperm and the amount per unit of volume was observed in animal and human studies. The effects seem to be dependent on how much is consumed, with frequent high doses suggesting a link to decreased sperm production.
• Sperm morphology: In both animal and human models, cannabis use was linked to more sperm defects (though the genetic material was found to be preserved).
• Sperm motility: Sperm’s ability to swim depends on mitochondrial function (energy), which was shown to be decreased with cannabis exposure. Again, this was found to be a dose-dependent relationship where higher doses or chronic use saw more significant effects.
• Hormones: Cannabis lowered the output of luteinizing hormone (also known as LH, which is responsible for testosterone production) from the pituitary gland, however the results on follicle-stimulating hormone (FSH) and testosterone varied (although FSH did decline with high doses of marijuana over four weeks).

Does marijuana affect pregnancy?

THC crosses the placenta, which means it can impact the fetus (and if you’re breastfeeding/chestfeeding, know that it also accumulates in breast milk).

Cannabis use during pregnancy has been connected to pregnancy-related anemia and, for the baby, lower birth weight and higher NICU admissions. That’s why both the American College of Obstetricians and Gynecologists and the Society of Obstetricians and Gynecologists of Canada discourage marijuana use during pregnancy and lactation. Longer term studies on childhood outcome suggest that children exposed to cannabis in utero may have lower test scores for memory and learning until they are four years old.

But what about CBD?

While the studies mentioned above look at cannabis as a whole—which means THC and the non-psychoactive compound CBD—you may have heard that products that contain just CBD (no THC) are lower risk. You might have even heard that CBD helps fertility because of its anti-inflammatory properties, but there’s simply no research to back those claims and its other effects may offset those benefits (we recommend turning to anti-inflammatory nutrients like DHA, Resveratrol, CoQ10 and NAC instead, which can all be found in The Power Prenatal for Females and The Powers for Males). When it comes to pregnancy and breastfeeding/chestfeeding, the FDA strongly advises against the use of both THC and CBD in any form. While there’s still a need for more studies, when you’re trying to conceive, your best bet is to talk to your doctor and err on the side of caution.