The Emerging Link Between THC & Fertility

Emerging research indicates that regular THC use may have a negative impact on fertility for both individuals who menstruate and folks who can inseminate others. Ongoing research is being done to provide more insight into whether these negative impacts are permanent, or if they may be able to be reversed.

THC, the Menstrual Cycle, & Reproductive Hormones

In 2021, a study of eight non-human primates at the Oregon National Primate Research Center at Oregon Health & Science University examined the impact of daily THC consumption on subject’s menstrual cycle and reproductive hormones over the course of three months (Ryan et al., 2021). The non-human primates ingested THC edibles that gradually increased in dosing, reaching a maximum of 2.5mg of THC (Ryan et al., 2021). Dosing was gradually increased based on documented dose increases recommended for humans to allow proper acclimation.

Results of the study showed that as the dose of THC increased, so did disruption of menstrual cycle lengths for subjects. Subjects had prolonged menstrual cycles or other abnormal cycles compared to their normal cycle lengths (Ryan et al., 2021). Subjects also had increased follicle stimulating hormone (FSH) levels, which is a hormone that impacts ovary funcitoning. These results strongly suggest a cause and effect link between regularly consuming high doses of THC and dysregulated menstrual cycles and reproductive health, although further study is needed in human subjects to corroborate these findings.

THC & Sperm Abnormalities

Research into the impact of THC on sperm health using human participants is a growing area of interest to researchers. A study conducted over a nine month period analyzed the semen of 409 participants seeking fertility support, of which 17% reported currently using marijuna and 25% reported using marijuana in the past (Hehemann et al., 2021). The semen analyses results demonstrated that current and past marijuna users had a statistically significantly higher likelihood of having abnormal sperm strict morphology compared to participants who had never used marijuana, and were also more likely to have lower semen volume compared to the World Health Organization reference value (Hehemann et al., 2021). Interstingly, participants who used marijuna had higher sperm motility than non-users, suggesting marijuna use may be a protective factor against low sperm motility (Hehemann et al., 2021). Further research is needed to corroborate the study findings, yet this prospective analysis suggests that marijuana use may have a detrimental effect on semen quality.

References

Hehemann, M. C., Raheem, O. A., Rajanahally, S., Holt, S., Chen, T., Fustok, J. N., Song, K., Rylander, H., Chow, E., Ostrowski, K. A., Muller, C. H., & Walsh, T. J. (2021). Evaluation of the impact of marijuana use on semen quality: A prospective analysis. Therapeutic Advances in Urology, 13, 175628722110324. https://doi.org/10.1177/17562872211032484

Ryan, K. S., Mahalingaiah, S., Campbell, L. R., Roberts, V. H. J., Terrobias, J. J., Naito, C. S., Boniface, E. R., Borgelt, L. M., Hedges, J. C., Hanna, C. B., Hennebold, J. D., & Lo, J. O. (2021). The effects of delta-9-tetrahydrocannabinol exposure on female menstrual cyclicity and reproductive health in rhesus macaques. F&S Science, 2(3). https://doi.org/10.1016/j.xfss.2021.05.001