Smoking recreational cannabis is now legal in Canada. But how much do you really know about its long term effect on your fertility? Does legal equal harmless?
Cannabis is the most commonly used drug in North America. According to Statistics Canada, about 45% of Canadians aged 15 and older indicated that they had used cannabis in their lifetime, and 15% reported using cannabis in the last three months.
There is a growing concern that legalization may reinforce the reputation of cannabis being a harmless drug and increase its use even further.
Cannabis, also known as marijuana among other names, is a psychoactive drug from the hemp plant, Cannabis sativa. The two main active substances of cannabis are tetrahydrocannabinol (THC), and Cannabidiol (CBD). THC is primarily responsible for the psychoactive effects or ‘high’ associated with cannabis use. Cannabis can be used by smoking, vaporizing, within the food, or as an extract.
According to an in-vitro study, researchers found a dose-dependent decrease in sperm motility. Which means higher doses of THC resulted in more slow-moving sperm. Borderline sperm quality was more susceptible to THC exposure and demonstrated a higher reduction in motility. In addition, THC exposure caused impairment in the ability of the sperm bind and penetrate the egg.
Another study investigating sperm quality in 662 men who smoked Marijuana, demonstrated contradicting results. In this study, men who smoked Marijuana had higher sperm counts. The researchers commented in their study that these results need to be interpreted with caution, and they highlighted the need for further research to determine the long term effects of Marijuana use on male fertility.
Marijuana has been shown to disrupt a woman’s ovulation. Evidence suggests that cannabis can reduce female fertility by disrupting the release of gonadotropin-releasing hormone (GnRH), leading to reduced estrogen and progesterone production, which can delay ovulation.
However, self-reported survey data have failed to link marijuana with infertility. According to a recent online survey, tracking the fertility rates of 1125 couples who self-reported marijuana use concluded that neither male nor female marijuana smoking reduced fertility.
TCH can cross from the placenta into the baby’s circulation and is also found in breastmilk of users. THC, therefore, can potentially affect the growth and development of the baby. Research suggests that cannabis use during pregnancy significantly decreases fetal folic acid uptake. Low levels of folic acid during pregnancy are associated with higher rates of miscarriages, as well as neural tube defects and low birth weight.
The Society of Obstetricians and Gynecologists of Canada recently published a statement urging pregnant and breastfeeding women to avoid cannabis.
In summary, the research so far on marijuana has demonstrated mixed results. Although many laboratory studies have shown harmful effects on sperm, eggs, and early pregnancy, more reliable evidence from large studies in humans is still needed.
Juno Fertility, in collaboration with Anova Fertility, is currently researching the effect of cannabis on IVF outcome so we can provide more sound advice to our patients.
In the meantime, we strongly recommend all our patients to avoid using cannabis when trying to conceive. It is a small lifestyle change that could optimize your chances to conceive.
If you wish to learn more about this study, please feel free to email us firstname.lastname@example.org.