Cannabis compounds could affect developing babies, U of A study says

New research from University of Alberta biologists says some of the key compounds of cannabis could be detrimental to developing babies

The research, published this month in the journal Scientific Reports, studied the effects of tetrahydrocannabinol (THC) and cannabidiol (CBD) in zebrafish embryos.

"The cells, the proteins, the receptors, the enzymes, the way the cells communicate in zebrafish is very, very similar to humans," U of A biology professor Declan Ali told CBC's Radio Active.

Zebrafish also have similar THC and CBD receptors to humans.

"We think that what we can learn from zebrafish we can take as a great starting point," said Ali, one of four authors of the study. 

At a critical stage of development known as gastrulation, zebrafish embryos were exposed to various levels of THC and CBD for about five hours. In humans, gastrulation occurs in the third week of embryo development — "early enough that pregnancy may remain undetected," the study notes.

Higher concentrations resulted in lower survival rates for the zebrafish. Researchers also found slower heart rates in almost all those exposed. As well, growth patterns of embryos exposed to the compounds differed from those of the control group.

"There were deformities," Ali said.

The researchers used much higher concentrations of THC than what is typically found in the blood plasma of humans after smoking cannabis. The amount was 10 times what is normally found, but only to account for the increased potency of THC in cannabis produced today.

Ali said it's tough to translate the results directly to the effects of THC and CBD on humans, but without experimenting on humans to test the effects of cannabis, zebrafish might be as good an indicator as any.

"I think what it tells us or what it suggests to us is exposure to these compounds may have an effect on a developing organism," he said.

"That's something to bear in mind if you are thinking of having kids."