Cannabis use during pregnancy raising concern about birth risks 

Researchers say an increase in emergency room visits and hospitalizations related to cannabis use by pregnant women is raising concerns.

Researchers say an increase in emergency room visits and hospitalizations related to cannabis use by pregnant women is raising concerns about risks including preterm labour, low birth weight and negative effects on the baby’s developing brain.

Their study was based on data from 980,398 pregnancies in Ontario among 691,242 people between January 2015 and July 2021. Of those, 540 individuals visited an ER or were hospitalized for cannabis use.

The rate of ER and hospital visits related to cannabis use during pregnancy increased to 20 per 100,000 pregnancies, up from 11 per 100,000 since legalization. The study found some patients were intoxicated or “very high” when they sought care, the lead researcher said.

Dr. Daniel Myran, a family physician and addiction specialist, said while the absolute increase in ER visits and hospitalizations was low, many more people may be using cannabis during pregnancy and not ending up in hospital.

“If that’s the case, I think it has important implications for the health of children who will be born from these pregnancies,” said Myran, a fellow at the Bruyere Research Institute and The Ottawa Hospital.

Some of the patients had a cannabis use disorder and were unable to stop using, while about 22 per cent experienced withdrawal, he said.

“This is not someone who used cannabis once or twice during pregnancy,” said Myran, also a post-doctoral trainee at ICES, formerly known as the Institute for Clinical Evaluative Sciences.

The study, which also involved Unity Health Toronto, was published Tuesday in the Canadian Medical Association Journal (CMAJ).