THC Can Impair Female Fertility, Study Finds
Eggs exposed to THC are significantly less likely to result in a viable pregnancy, according to a new study due to be published in the Journal of the Endocrine Society.
After dosing cow oocytes (egg cells) with the cannabis compound, the study’s authors found that high concentrations of THC significantly reduced the number of cells that matured into embryos.
As marijuana use among reproductive-age men and women increases, the study’s findings could help physicians to better advise patients undergoing in vitro fertilisation (IVF).
Cows and (m)oocytes
To get their results, the researchers treated cow oocytes (a standard substitute for human egg cells) with different concentrations of THC, which were roughly equivalent to different recreational doses. Oocytes were either treated with low THC, mid THC, or high THC concentrations, treated with an ethanol mixture, or left untreated in the control group.
Just over 70 percent of oocytes treated with the high THC dose (3.2uM) reached the egg cleavage stage, when the cell starts to divide and mature into an embryo. This figure was significantly lower than the 86.9 percent of eggs that successfully cleaved in the control group.
“This is a key indicator in determining the quality and developmental potential of the egg,” said Megan Misner, who was part of the study’s research team from the University of Guelph, Canada.
Notably, THC didn’t have a significant effect on the development rate of a dividing egg (blastocyte). This suggests that THC exposure mainly affects the chances of an egg cleaving and not the stages that follow. Nevertheless, blastocytes from the low THC group did contain significantly lower levels of protein channels associated with higher quality embryos.
“This [kind of] embryo would be less likely to proceed past the first week of development, and thus lead to infertility,” Misner said in a statement.
THC and fertility
Misner’s findings could have wide implications for cannabis-using couples looking to conceive with IVF. And beyond conception, recent research has shown that resuming cannabis use throughout a pregnancy has its downsides, too.
A paper published in Nature Neuroscience last October found that THC exposure in the womb could leave children vulnerable to psychotic experiences in early life. Fortunately, the same study also discovered that these symptoms could be reversed with a dose of pregnenolone, an FDA-approved drug and diet supplement.
But, speaking to Analytical Cannabis last year, the study’s lead author advised that the best method for preventing such effects is avoiding cannabis all together while pregnant.
“Forty percent of Americans would think that it's okay to smoke marijuana when you're pregnant, and our study clearly says that is not okay at all,” said Miriam Melis, an associate professor of pharmacology at the University of Cagliari, Italy.
“Would you give a joint to a kid?” she asked. “I think you wouldn’t. So why would you need give it to a fetus?”