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

Unofficial holidays: Here’s what people are celebrating for the week of Sept. 27 to Oct. 3

World Farm Animals Day, Drink Beer Day and Virus Appreciation Day are all coming up this week

COVID-19 cases grow to 13 at B.C. First Nation near Fort St. James

“This is very serious,” says Nak’azdli Whut’en Chief

Cullen confirmed as B.C. NDP candidate for Stikine despite party’s equity policy

Former Tahltan Central Government President Annita McPhee said the process made her feel “abused”

Freeport — the camp site that was the region’s largest community

A story of the construction of the Grand Trunk Pacific Railway

105 new COVID-19 cases, 1 death as health officials urge B.C. to remember safety protocols

There are currently 1268 active cases, with 3,337 people under public health monitoring

B.C. nurses report rise in depression, anxiety, exhaustion due to pandemic

A new UBC study looks into how the COVID-19 response has impacted frontline nurses

National child-care plan could help Canada rebound from COVID-induced economic crisis: prof

A $2 billion investment this year could help parents during second wave of pandemic

Search suspended for Indigenous elder last seen mushroom picking in northwest B.C.

Mushroom picker Thomas (Tommy) Dennis has been missing since Sept. 16

16 MLAs retiring from B.C. politics add up to $20M in pensions: Taxpayers Federation

Taxpayers pay $4 for every dollar MLAs contribute to their pensions

Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

‘Bonnie’ and ‘Henry’ among latest litter of service dog puppies

B.C. Alberta Guide Dogs names two pups after provincial health officer

Permanent fish-passage solutions considered at Big Bar landslide

151,000 salmon detected this year north of site

B.C. VOTES 2020: Few solutions offered for ‘out of control’ camping

B.C. Liberals, NDP spend millions as problem keeps growing

Most Read