January 1998. An ice storm plunged more than 3 million Quebecers into darkness for 45 days. It was an unforgettable natural disaster, especially for Suzanne King, a researcher at the Douglas Mental Health University Institute. She saw it as a unique opportunity to study the effects of stress on pregnant women and their future children. Two hundred women were recruited, and her Project Ice Storm took off. Twenty years later, her team is still following about a hundred of these children.
“After two decades of uninterrupted research, we continue to publish results showing the significant long-term effects of exposure to prenatal stress on the growth, behaviour and cognitive and physical development of Project Ice Storm children,” says King, a full professor in McGill University’s Department of Psychiatry.
Children’s health and development at stake
Project Ice Storm has shown that maternal stress has an impact on different aspects of children’s development, such as their intelligence quotient (IQ), autism-related traits, bilateral coordination, and brain structure.
For instance, King and her team have shown that:
- Children whose mothers had been exposed to significant objective prenatal maternal stress (e.g., the number of days without power) had lower IQs. These children had less-developed language and cognitive skills than those whose mothers had not experienced such a high level of objective stress.
- The higher the level of the mothers’ objective difficulties (e.g., the length of the power outage) due to the ice storm, the more severe their children’s autistic traits were at the age of 6½ years.
It should be noted that many of these associations are moderated by the timing (trimester) of the exposure during gestation or by the child’s gender.
The latest studies published in 2017 by King’s team on ice storm mothers and children indicate that the more difficult the hardship endured by the mothers, the higher the girls’ body mass index was at the age of 5½ years and the more predictive it was, therefore, of earlier puberty (age of first premature menstruation). Furthermore, the size of the effect of maternal stress on the children’s body mass index increased as the children grew older.
“These results show how a stressor during pregnancy can influence both the physical development and mental health of the unborn child,” explains King.
Her team is now looking at reproductive organ development in the young men and young women to determine if there are any observable changes that might be associated with prenatal stress. These results will be made known in 2018. Similar experiences in other countries Natural disasters have an impact on pregnant women, regardless of where they occur.
This said, in 2008, King worked with a group conducting research on pregnant women affected by floods in Iowa, in the United States. In January 2011, the Australian state of Queensland experienced severe flooding, too. In this case, King combined a study on disasters with an existing study on pregnant women whose psychosocial data were available prior to the flood. In a recent research project, she studied the impact of the Fort McMurray, Alberta, fire on pregnant women (2016). Lastly, her latest study looked at pregnant women during Hurricane Harvey, which, in August 2017, struck Houston, Texas, where 72,000 women give birth each year.
To better cope with natural disasters, future mothers are advised to limit their exposure to the stressor, such as by staying with relatives outside the affected area. Seeing the experience in a positive light can also help, as this has a significant impact on the child’s brain. They can also reduce their stress level by eating and sleeping well or exercising.
This research was funded by grants from the Canadian Institutes of Health Research, the National Institute of Mental Health and the March of Dimes.
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