The children of women who smoke while pregnant have significantly thicker and denser arteries, suggests a new study.

Thicker arterial walls can increase a person’s risk of developing obesity and heart disease.

Researchers in the Netherlands studied 259 children to determine the effect of smoking on the thickness of their carotid artery and its elasticity.

Children of mothers who smoked throughout their pregnancies had significantly thicker and more rigid arteries at five years of age than children whose mothers had not smoked.

The arteries were the thickest in children whose parents had both smoked during pregnancy.

In children whose mothers had not smoked in pregnancy but resumed after their birth, the arteries were not found to be thicker.

Children were assessed through ultrasound at four weeks of age and then at five years of age. Smoking during pregnancy was defined as smoking a minimum of one cigarette per day for the duration of the entire pregnancy.

Smoking data was determined via questionnaires.

"Exposure of children to parental tobacco smoke during pregnancy affects their arterial structure and function in early life," write the authors.

"Moreover, there was a clear positive trend between the number of cigarettes smoked by mothers in pregnancy and adverse vascular health, a finding that adds to the credibility of gestational smoking being causally related to offspring vascular damage."

The current study is part of a large population-based birth study that started in December 2001 and is still ongoing.

The research is published in Monday's issue of the journal Pediatrics.