Babies whose mothers do not eat enough during pregnancy appear to be at risk of clogged up arteries later in life, researchers say.

A study of 200 children found that, on average, the lower the mother's caloric intake during pregnancy, the thicker the child's artery walls.

Clogged up arteries - atherosclerosis - can lead to heart disease and strokes.

The University of Southampton team said the reasons for the apparent link were unclear and needed further exploration.

Their study appears in Arteriosclerosis, Thrombosis and Vascular Biology.

The researchers used ultrasound scans to measure the thickness of the wall of the carotid artery in more than 200 nine-year-old children whose mothers had taken part in a nutrition study during pregnancy.

Experts usually say a pregnant woman needs to eat around 2,500 calories per day.

'Total calories key'

The researchers said it did not matter what proportion of the calorie intake came from fat, protein or carbohydrate - it was the total calorie intake that was important.

The association between artery thickness and calorific intake remained strong even after taking account of factors such as social class, smoking, exercise habits and sickness in pregnancy.

The study also found that children who were heavier, those who had higher blood pressure or those who took less exercise were more likely to have thicker artery walls.

Researcher Dr Catharine Gale said atherosclerosis was a progressive condition that started early in life.

"Our study provides direct evidence for the first time in humans that the mother's diet in pregnancy might influence the child's susceptibility to atherosclerosis.

"The exact reasons why lower maternal energy intake in pregnancy was linked to increased arterial wall thickness in the children are unclear.

"We need to do further studies to see if the same findings are present in other groups of mothers and children and to explore explanations for the link.

"One possibility is that maternal energy intake in pregnancy may affect the child's blood cholesterol concentrations.

"Children who have higher blood cholesterol concentrations are at increased risk of atherosclerosis."

Judy O'Sullivan, a cardiac nurse at the British Heart Foundation, said: "This study indicates that a low calorie intake during pregnancy affects the thickness of the carotid artery.

"This thickness can be a good indication of athersclerosis in adults but more work needs to be done before we can say the same is true for children.

"Our advice to pregnant women is that a healthy balanced diet is essential to give both mother and baby the best chance of a healthier life.

"A restricted or low calorie diet should not be followed during pregnancy."