Mothers who smoke while pregnant could be increasing the chances of their children having heart disease in later life by up to 15pc, according to research published today.
Smoking in pregnancy lowers a type of cholesterol known to protect against heart disease, called high-density lipoprotein (HDL) cholesterol.
Children of mothers who smoked while pregnant had HDL levels 10pc lower than those whose mothers did not smoke, found Australian researchers.
While the normal level in children was 1.5 mmol/L (millimoles per litre - used to measure very low concentrations of substances in blood), after adjusting for various factors the level in children with smoking mothers was 1.35 mmol/L.
The researchers were confident the difference was caused by exposure in the womb, because it was independent of whether the children had been exposed to passive smoking after birth.
David Celermajer, Scandrett Professor of Cardiology at the University of Sydney, who led the study, said: "Our results suggest that maternal smoking ‘imprints’ an unhealthy set of characteristics on children while they are developing in the womb, which may well predispose them to later heart attack and stroke. This imprinting seems to last for at least eight years and probably a lot longer."
He added: "If we extrapolate this, we can suggest that the difference of 0.15mmol/L between children of smoking mothers versus non-smoking mothers might result in a 10-15pc higher risk for coronary disease in the children of smoking mothers.
"This is an approximation only, but the best one we have."
The study is published online in the European Heart Journal.
Amy Thompson, senior cardiac nurse at the British Heart Foundation, said: "More research is needed to reveal the biological mechanics behind this link. However, mothers-to-be should not wait for this.
"Smoking during pregnancy poses many other well established risks to women and their unborn babies, and this study adds to that evidence.
"Stopping smoking has huge health benefits, so if you smoke and are pregnant, or plan to be, contact your GP for advice and support to help you quit.”