A handful of cannabis bud is shown in Fenwick, Ont., on Tuesday, June 26, 2018. THE CANADIAN PRESS/Tijana Martin

Researchers find cannabis use in pregnancy linked to greater risk of autism

Researchers caution findings only show association — not cause and effect

A new study links cannabis use in pregnancy to a greater risk of autism.

Researchers including experts from the Ottawa Hospital and the University of Ottawa reviewed data from every birth in Ontario between 2007 and 2012, before recreational cannabis was legalized.

They found 1.4 per cent of 18-month-olds were diagnosed with autism but that rate was higher among children exposed to cannabis in the womb, at 2.2 per cent.

RELATED: New study suggests autism overdiagnosed: Canadian expert

RELATED: Surf’s Up Tofino offers wave of positivity for families living with autism

Of roughly 500,000 women in the study, 3,000 reported cannabis use during pregnancy. The analysis focused on 2,200 women who said they only used cannabis during pregnancy, and no other substances.

Researchers don’t know how much cannabis was used, how often, at what stage of their pregnancy, or how it was consumed. They also caution the findings only show association — not cause and effect.

The findings were published today in the medical journal Nature Medicine.

Even though recreational cannabis is now legal and more socially acceptable, study co-author Dr. Darine El-Chaar says that doesn’t mean it’s safe for people who are pregnant or breastfeeding.

El-Chaar says cannabis use seems to be more prevalent, with her patients much more open about telling her it helps ease their morning sickness or pain.

“Our answer is still that we don’t have correct, properly made studies that are designed to look at this question,” says El-Chaar, a maternal-fetal medicine physician and clinician investigator at the Ottawa Hospital and assistant professor at the University of Ottawa.

Researchers had previously found that cannabis use in pregnancy was linked to an increased risk of preterm birth. That study also found pregnant women who used cannabis often used other substances including tobacco, alcohol and opioids.

Funding came from the Canadian Institutes of Health Research.

— By Cassandra Szklarski in Toronto

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Mission couple cry fowl over District bylaw cracking down on backyard chickens

Bylaw enforcement letter states couple need to egg-vict hens or face daily $450 penalty

Chilliwack man pleads guilty to violent assault of elderly man in Abbotsford

Victim, 85, attacked while waiting at bus stop in November 2019

Staff shortages plague Mission Institution following recovery from COVID-19 outbreak

Guards at 60% of workforce; inmates suffer daily with lockdown, mental health issues

Long-term planning for jewel known as Vedder Greenway starts with survey

It’s the most popular trail system in Chilliwack with a half million local and LM users each year

Westbound Highway 1 stall in Langley blocking left lane

Congestion starting at 264th Street, crews on scene

B.C. counts 125 new COVID-19 cases, up to 1,284 active

No new deaths or health care facility outbreaks

Chilliwack man, 31, in critical condition after altercation at Langley university

RCMP received a report of an ‘agitated man’ on TWU campus

B.C. VOTES 2020: Wilkinson to stop 24-hour camping in city parks

Ban on ‘unsafe roadside panhandling’ to be enforced

Lessons from a pandemic: How to design a nursing home that’s safe and love-filled

A look at how one care home is battling the pandemic with the social needs of the elderly in their care

Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

Winter tires, chains now mandatory along most B.C. highways

Drivers without the proper winter tires – which must also be in good condition – can be fined $109

Health Canada green-lights rapid COVID-19 test

Health Canada approved the BCube test from Hyris Ltd. in the United Kingdom Sept. 23

First Nations Health Authority chief medical officer concerned with rising COVID-19 cases

“There’s still so much we don’t know and we’re learning everyday about this particular virus.”

FINLAYSON: COVID-related job losses concentrated in urban areas… especially Metro Vancouver

The biggest job losses, in absolute terms, have been in Metro Vancouver

Most Read