What the ice storm can teach us about the prenatal impacts of pandemic stress

In 1998 Suzanne King's family was one of hundreds of thousands who were left without heat and power after a massive ice storm devastated much of Quebec's electrical infrastructure. In different areas it took days — or even weeks — to restore power. 

It was an enormously stressful time. And that led King, a professor in the department of psychiatry at McGill University, to begin a two-decade-long study of the children of women who were pregnant during the ice storm. She found a wide range of often subtle impacts in these children on body weight, temperament, cognitive function and even co-ordination — all apparently due to the stress their mothers experienced.

The greater the amount of stress on the mother, the greater the amount of change we see in the kids.- Suzanne King

She told Quirks & Quarks host Bob McDonald that this work could have implications for understanding the potential impacts of the stress of the COVID-19 pandemic as well.

"The scope of this pandemic is global. I mean literally there's nobody that is unaffected by it. So that level of stress is very high," said King. "So this is a highly stressful situation and all reports are that pregnant women are being especially stressed out at this time."

Ice storm anxiety led a study of long-term impacts

In 1998, King had already been interested in the impacts of stress from natural or man-made disasters on development in pregnancy. It was, however, a difficult thing to study. Then the ice storm presented her with a natural, if tragic, experiment.

Her own family was without power for a week, but after their power was restored, she had a routine blood pressure check. Her blood pressure was far higher than normal. There was a clear cause for this, she knew.

"That's residual stress from seven days without electricity in the coldest month of the year," said King.

"It occurred to me that if I was feeling stressed and anxious, that there were gonna be a lot of pregnant women out there who were also feeling that way."

King began a project in which she recruited a large number of women who were pregnant during the ice storm disaster, and followed the development of their children throughout their infancy, childhood and adolescence. Nearly 100 families continued to be followed until the children were 19 years old.  

The impact of the ice storm related stress was clear.

"Across every aspect of the kid's development we have seen what we call a dose response kind of effect," said King. 

The longer the mother was without power in the aftermath of the ice storm, the more stress she experienced.

"The greater the amount of stress on the mother, the greater the amount of change we see in the kids," King said.

"If we just separated the children of mothers who had, say, 20 days or more without electricity and other kids whose mothers had maybe 10 days or fewer without electricity, we have like a 10 or 12 point difference in their IQ, which is quite sizeable."

King cautions that these effects were observed statistically in large groups of children.

"You wouldn't be able to point at one person and one particular issue and say that that was because of the ice storm," she said.

Nevertheless, in the group of children, the range of impacts was wide and included behavioural problems in school and at home, risks of obesity and diabetes, and deficits in physical co-ordination.

The kinds of impacts also depended on when during pregnancy the mothers experienced the stress. If the mothers were in the first trimester, there was an increased risk of what King calls "autistic-like symptoms." If the mothers were in their third trimester, there was an increase in impact on motor development. This, she speculates, has to do with what parts of the fetal brain are developing at those times.

We can limit change by trying to keep it a regular routine as much as possible.- Suzanne King

King's team is still working to understand the mechanisms for how prenatal stress impacts these developmental differences, but they suspect a significant factor is changes in the children's gene regulation, or epigenetic factors, driven by the mother's stress response.  

"You cannot change a person's DNA, but along the DNA there are these little spots that are a little bit like little switches that turn different genes on and off according to the environment. So it's a little bit like a piano. You can't change the keys on the piano, but you can play a different tune," she said.

What this means for the COVID-19 pandemic

King has studied the impacts of other stressful disasters on prenatal development as well as the ice storm, including the wildfire in Fort McMurray, Alta., in 2016, the flooding in Iowa in 2008, and flooding from Hurricane Harvey in Texas in 2017.

She's found several factors that seem to exacerbate stress in these situations, including the degree of loss in the disaster, the scope, the intensity of the threat and the degree of change. Unfortunately, she says the current pandemic checks all of these boxes.

Loss, for example, is extreme for many people.

"If you think about the loss throughout the population, there are very high levels of financial loss and loss of freedom, loss of all kinds of things," she explained. 

And the stressful change in circumstances is also high, she says.

"Even if you don't have the virus, everything about going to the grocery store, everything about our work, everything about recording an interview on the radio — everything is different than it would've been before."

But King suggests there are some ways pregnant women might reduce the stress of this experience and help mitigate the developmental risks.

"If you think about threat, pregnant women can limit their threat, you know. Stay inside, follow the directives, keep washing hands, let other people go to the grocery store. So one can limit the threat," she said.

"We can limit change by trying to keep it a regular routine as much as possible. Going to bed at the same time, waking up at the same time, getting dressed as you would if you were going into work, or it were a regular day."

She also suggests that simply focusing on what positive elements of this experience there might be — what is known as "cognitive appraisal" — can help. This might be focusing on time spent with family, or the generosity of friends and neighbours, for example.

"As much as possible, if people can look for positive things about what's happening during the pandemic, that will help the mother probably, but may also have effects downstream on the mother's fetus."

Produced by Sonya Buyting. Written by Jim Lebans.