Ice storm stress affected pregnant women's offspring, study suggests

The stress and level of hardship faced bypregnant women during the 1998 Quebec icestorm may have affected the health of the children they gave birth to, researchers say.

In Quebec, the ice storm caused widespread power outagesand millions of people went without power for long periods afterheavy icetoppled power pylons.

Scientists from the Douglas Mental Health University Institute and McGill University have been following a group of 150 familiesin which the mother was pregnant during the natural disaster. They found that the number of days a woman went without electricity influenced the genetic expression of her child.

In 36 of the children examined, researchers found theDNA inside a type of immune system cell called a T cell was modified. They say this type of DNA modification, called methylation, affects howgenes are expressed.

The health effects of the change in genetic expression aren't clear, but researchers sayit could put children at a greater risk to develop asthma, diabetes orobesity.

The goal of the study was to see if maternal stress affects the health of children.One of the researchers involved,McGillUniversity pharmacology and therapeutics professorMosheSzyf, says researchers haven't been able to examine this before.

"We have evidence in animals that if you stress an animal during the pregnancy that will have long-term effects in the way the DNA is programmed and the way their health shapes up later in life. But we didn't know if this can happen in humans because it's unethical to stress little babies," he says.

Szyfsays this study is the first to show that objective stress, such as the number of days a woman went without electricity, is what causes long-lasting changes in genetic expression and not the degree of emotional stress.

Results of this study have been published in the international online publication Plos One this month.

Szyf says the research need to be replicated in a larger study, but that it highlights how important it is to keep a non-stressful environment for pregnant women.