Smoking during pregnancy more damaging than first thought

In the Media
In a world-first Researchers at the Heart Research Institute and the University of Sydney believe they’ve found evidence that women who smoke while pregnant affect their child's cardiovascular health for years to come.

The study found pre-natal exposure to a mother's smoking decreased the amount of good cholesterol in children which may increase the risk of eventual heart attacks and strokes by up to 20 per cent.

The results were more significant than expected. 

“We were gobsmacked,” said David Celermajer, Clinical Research Group Leader at the Heart Research Institute and a professor of cardiology at the University of Sydney.

He and his colleagues studied 328 healthy 8-year-olds and found some bore the lingering imprint of their mother's smoking while pregnant.

“Most studies suggest that if you stop smoking eight years later a lot of your risk has reduced,” said Professor Celermajer.

“The reason we were gobsmacked is here are kids who were exposed to another person's smoke when they were growing in their mum's belly and eight years later, eight years after being removed from that insult they've still got a footprint on it. That's the staggering part."

"To the best of my knowledge no-one has ever shown before that smoking in pregnancy has a prolonged effect on body changes in offspring.”

The study's results, published today in the European Heart Journal, relied on questionnaires about the mother's smoking filled in shortly after the children's birth and blood samples from the children.

The researchers found the children whose mothers reported smoking while pregnant had less high-density lipo-protein or so-called good cholesterol than children whose mothers hadn't smoked.

That cholesterol protects against heart disease.

The study found the smoking mother's children have 1.3 millimoles per litre of the cholesterol compared to a more normal level of 1.5 millimoles, a significant difference according to Professor Celermajer. 

“I mean heart disease remains the number one killer in Australia, so even a small increase in risk above the general population represents a massive number of people that are potentially affected,” he said. 

“Roughly for every 1 per cent reduction in the good cholesterol there's a 1 per cent increase in heart attack risk and what we've found in this study is up to a 20 per cent reduction in the good cholesterol levels of these children of mums who have smoked during pregnancy.”

“And so we postulate that they're up to 20 per cent risk higher of heart attack and stroke during their lifetimes.”

Professor Celermajer says this was a wake-up call for all Australian. 

“For kids whose mums did smoke - and they can't wind back the clock now - they have to be particularly careful of the way they live their lives to maximise their heart health by not smoking themselves and by having healthy diet and exercise habits.” 


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