Cannabis & the Impact on Egg Quality

By: Jess Gardiner

In Canada, an average of 1 in 3 adults discloses cannabis use. Canada was one of the first countries to legalize cannabis in 2018. The goal of this was to protect youth, enforce advertising regulations to limit youth’s exposure, and to reduce criminal activity relating to possession. However, the consequences on human fertility due to the increased adult exposure has barely been researched, nevermind considered when instituting the Cannabis Act.

one significant study

The largest study in regards to cannabis impact on specifically female fertility was published in September of 2025 in the online journal Nature Communications. A control study was conducted in which patients undergoing the IVF cycle were compared on the basis of if they were consuming cannabis during their treatment cycle, and what the results of the cycles were.

It has been previously established that THC (Delta-9-tetrahydrocannabinol, or the cannabinoid responsible for the “high”) is found within the follicular fluid inside of the ovaries, which is the fluid directly housing human oocytes, or a woman’s eggs. This direct exposure of the oocyte to THC is detrimental, and believed to lead to an increased risk of chromosomal abnormalities within the embryo.

The increased risk of chromosomal abnormalities was determined through PGT testing on both the oocytes before fertilization and the embryos that successfully developed to the blastocyst stage. PGT testing on the eggs looks at spindle morphology, or the shape of the structures that separate chromosomes, to assess their maturity and the likelihood of successfully developing further after fertilization. PGT testing on the embryos counts each of the chromosomes and their arms, to ensure there are exactly 46 and that they are each properly formed. This method of testing remained consistent in that the spindle morphology in the egg could predict the likelihood of a euploid (x46 chromosomes) or aneuploid (+/- 46 chromosomes) embryo. 

egg maturation & thc

The laboratory team also introduced THC1 & THC2 to any immature oocytes retrieved, to determine whether THC was affecting the maturation rate. It was discovered that THC did very slightly increase oocyte maturation compared to immature eggs not exposed to THC given the same amount of time to mature, however the discrepancy between the two was not significant. 

higher risk of chromosomally abnormal embryos

Of the patients whose follicular fluid tested positive for THC, over 70% did not disclose cannabis use on intake documents. After the PGT results on the embryos came back, it was found that the embryos made with eggs exposed to THC were 9% more likely to be aneuploid and have chromosomal abnormalities. THC also increased the likelihood that of the aneuploid embryos, a greater ratio are considered ‘complex’ aneuploids (having more than one chromosomal abnormalities) compared to the non-THC exposed aneuploid embryos. Though the risk of chromosomal defects was found to be greater, the successful fertilization and blastocyst rates were not impacted.

hormonal considerations

Not only were the eggs directly impacted by THC through the follicular fluid, but cannabis also impacts the amount of hormones our brain releases into the rest of our body. Regular cannabis users were found to produce less GnRH (gonadotropin releasing hormone) from the hypothalamus region in the brain, which then reduces the amount of FSH (follicle stimulating hormone) and LH (luteinizing hormone) released by the pituitary gland. FSH and LH are vital for follicular development and ovulation, and so women who have reported long-term cannabis use have also had correlation with irregular menstrual cycles and anovulation. There have not yet been enough studies done on this topic, or the possibility of THC affecting endometrial response and receptivity due to these hormonal fluctuations, potentially decreasing the likelihood of a successful embryo transfer.

In summary, the use of cannabis could jeopardize the results of an IVF cycle due to the direct and indirect impacts that THC has on an oocyte. There have not been studies on if CBD alone may have a different outcome, however preliminary animal studies are showing similar results. It is best practice to be cannabis-free for at least 2 to 3 months before proceeding with an IVF cycle in order to maximize the chances of success!

curious if you qualify?

Disclosing your cannabis use does not disqualify you as an egg donor, but we understand if you have a few more questions! Book a consultation with a member of our donor team to discuss your specific lifestyle and other factors to determine your eligibility. Thank you for considering becoming a Helper!

bio

Jess Gardiner is an Egg & Embryo Donation Coordinator who is passionate about education and advocacy in the world of infertility. She shares this passion in an effort to beat the stigma surrounding infertility and make resources available to everyone, no matter where they are in their journey. Book a free consultation and learn how Jess can help guide you through the fertility frontier!