Female eggs exposed to THC, the psychoactive ingredient in marijuana, have an impaired ability to produce viable embryos, and are significantly less likely to result in a viable pregnancy, according to an animal study accepted for presentation at ENDO 2020, the Endocrine Society’s annual meeting… The eggs’ developmental rates and gene expression were measured. The researchers evaluated the ability of embryos to reach critical stages of development at specific time points. With higher concentrations of THC, they found a significant decrease and delay in the ability of the treated oocytes to reach these checkpoints.