A new study shows that cannabis use can affect fertility in women, EuroNews reported.

Scientists in Canada tested samples from women undergoing in vitro fertilization (IVF) and found that samples positive for tetrahydrocannabinol (THC) — the psychoactive ingredient in cannabis that causes the "high" – showed signs of poorer outcomes.

These signs included a lower number of chromosomally normal embryos, which is associated with failed implantation, miscarriage, and non-viability, according to the study published in the journal Nature Communications.

Canadian and Israeli scientists analyzed 1,059 samples of follicular fluid—the fluid in the ovaries that surrounds and nourishes the developing egg. Sixty-two samples contained THC metabolites, indicating cannabis use. It was these samples that showed abnormalities in the average number of chromosomes.

In laboratory tests on immature eggs from 24 donors, the scientists simulated the effects of THC. At concentrations similar to those in the positive samples, the substance more often caused errors in chromosome distribution, which could increase the likelihood of unsuccessful IVF.

It is noteworthy that the degree of egg maturation—the percentage of eggs that develop successfully and can be fertilized—is also affected by THC. However, the effect was only observed at THC levels higher than the average levels found in patient samples.

Lead author Cynthia Duval pointed out that the key advantage of their work is the ability to directly measure THC levels in samples, whereas most other studies rely on self-reporting, and many women do not admit to using cannabis.

"Our method gives us a much more accurate picture and helped us determine the exact concentrations for the laboratory experiments," explained Duval, now director of translational research at the Toronto-based CReATe Fertility Centre.

The authors note that the results apply only to a specific type of immature egg. The study did not account for factors such as the women's age, which also affects egg health, and it is unclear how often or how much cannabis the participants used.

Further research is needed to understand how cannabis affects pregnancy outcomes through the mechanisms identified. However, previous studies have shown a link between drug use and fertility, as well as between cannabis and sperm quality.

Experts emphasize that since cannabis is widely used, it is critical to understand its effects on people's mental, physical, and reproductive health, which would also help doctors better advise their patients. | BGNES