Marijuana and other drugs that interfere with the signaling system in the brain could have a negative impact on fetal development, according to researchers at the University of Aberdeen in Scotland.

The BBC reported June 16 that researchers said that pregnant women should avoid smoking marijuana or using other substances -- including drugs prescribed for obesity or other conditions -- that act on the brain systems that allow nerve cells to communicate.

"Our initial findings showed the importance of these naturally occurring molecules in guiding the growth and connections of nerve cells in the developing brain," said lead researcher Jan Mulder. "Now we demonstrate the extent of this signaling system and that complex network of neurons -- the backbones of higher cognitive functions -- do not develop normally when endocannabinoid signaling is disturbed."

"Our findings highlight that the integrity of this signaling system should be maintained and not disrupted if the brain is to develop normally," said researcher Tibor Harkany. "Anything that disrupts this process such as cannabis smoking or certain drugs that interfere with this signaling system could ultimately affect the brain's functionality."

The study was published in the Proceedings of the National Academy of Sciences.