Small study finds comparable IVF outcomes with marijuana smokers

Researchers in a 2021 study found comparable IVF outcomes and pregnancy rates in people who smoked marijuana, however this was a small study and used self-reported data.

Does marijuana (cannabis) use have an impact on IVF outcomes (number of eggs retrieved, fertilization rate, pregnancy rate, etc.)?

Marijuana use is increasing worldwide, particularly in areas where it’s become legalized, but its impact on fertility and pregnancy isn’t clear.

So what do we know?

We know a bit about its impact on male fertility (and unfortunately, not so much when it comes to female fertility). Payne et al. (2019), in their systematic review, found that marijuana use can compromise semen parameters in males (reducing sperm counts and motility and increasing abnormal sperm). Additionally, a study by Harlow et al. (2020) found an increased risk of miscarriage when males used marijuana >1 time/week (from 19% to 31%).

During pregnancy, Roncero et al. (2020) reviewed the data on the use of cannabis and the obstetric/developmental outcomes. They found associations with low birth weight, shorter birth length and a low head circumference, as well as an association with mood and behavioral disorders including anxiety, depression and ADHD.

In terms of IVF, a previous study by Nassan et al. (2019) compared couples that used marijuana to those that didn’t:

• Increase in pregnancy loss in couples where women were using marijuana at the time of enrollment in the study (54% vs 26%, based on 9 couples)
• Increase in live birth rates in couples where men were using marijuana at the time of enrollment in the study (60% vs 39%, based on 21 couples)
• Intensity of marijuana use was not associated with different outcomes
• Past and never users had similar success rates

Har-Gil et al. (2021) in their single-center, retrospective study, wanted to add to this by assessing marijuana use in couples undergoing IVF. By using a questionnaire, marijuana use was considered light if the participant reported marijuana up to 3 times a week, and heavy if they used more than 3 times a week.

There were a total of 654 non-user couples and 68 user couples:

• 15 couples in which the female used cannabis
• 40 couples in which the male used cannabis
• 13 couples where both male and female used cannabis

Yes, this isn’t a large study unfortunately. But it is what it is!

On to the results!

---

Results

They found no difference in:

• Number of mature follicles
• Number of oocytes retrieved
• Number of mature oocytes
• Peak estradiol
• Progressive motility
• Number of fertilized eggs
• Fertilization rate (ICSI and IVF)
• Blastocyst formation rate
• High quality blastocyst formation rate

There was also no difference in implantation rate (41.13% for non-users vs 40.74% for users) and ongoing pregnancy rates (29.10% vs 35.23%).

They did a subgroup analysis where they compared the light and heavy users, along with the couples where only the male or female used marijuana. In certain subgroups they found an increase in sperm volume (1.77 ml vs 3.53 ml for female user couples vs both user couples) and sperm quality (a score of 6 vs 5 for male user couples vs female user couples). Sperm was scored using concentration, motility and % normal, as poor (1-3), fair (4-6), and normal (7-9).

Conclusions

All the IVF outcomes were comparable between cannabis users and non-users. The ongoing pregnancy rate for users was slightly higher at 35.23% compared to 29.10%. Although this wasn’t statistically significant, the couples that used marijuana in this study were slightly younger (median age of 34 vs 36), which might account for this.

Even though previous studies have found an association with reduced sperm quality, this study actually found that those who used cannabis had the highest sperm volume and quality score!

This result is comparable with what Nasan et al. (2019) had found. In this study they compared semen in men who never smoked, past marijuana smokers, and current marijuana smokers:

• Past marijuana smokers had a higher sperm concentration compared to never smokers (62.7 million/ml vs 45.4 million/ml).
• No differences between current smokers and past smokers (59.5 million/ml vs 63.5 million/ml).
• No difference in sperm DNA fragmentation (SDF)

The main limitation of the study summarized here is that it’s small and represents only a single IVF center. The data is recent, and may be the first study to report on IVF outcomes in a country where marijuana is legalized. Previous studies that report on marijuana use were at times when it was illegal (where it’s quality wasn’t regulated). Another issue is that this is self-reported data from a questionnaire and it’s possible that non-users could have been lying about their use.

Reference

Har-Gil, E., Heled, A., Dixon, M. et al. The relationship between cannabis use and IVF outcome—a cohort study. J Cannabis Res 3, 42 (2021). https://doi.org/10.1186/s42238-021-00099-5

If you liked this post and want to support what I do, please consider a paid subscription, Patreon or donate through PayPal!

 

---

About Embryoman

Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.

---