London, Nov. 12: Pregnant women who lead a couch potato lifestyle are condemning their unborn children to an increased risk of asthma in later life, scientists believe.

Two studies will show that levels of vitamin D in mothers-to-be have a pronounced effect on the chances of their children developing the condition. Experts believe a lack of vitamin D, found in foods such as oily fish and boosted by exposure to natural sunlight, hinders the development of the child’s lungs and immune system while in the womb.

They fear that the offspring of pregnant women whose lifestyle consists of languishing in front of the television and eating unhealthy food are most at risk.

The first study, by US academics at Harvard Medical School in Boston found that children born to mothers with a vitamin D deficiency during pregnancy were up to twice as likely to develop wheeze, an early symptom of asthma, by the age of three.

In a second study, Graham Devereux, a senior lecturer at Aberdeen University, discovered that children whose mothers ate a diet rich in vitamin D during pregnancy were 60 per cent less likely to develop wheeze by the age of five.

Devereux carried out study on 1,200 mothers and their children. “The evidence indicates that maternal diet might be particularly important in the development of childhood asthma,” he said.

“Maternal diet affects the way the foetal lungs develop and we suspect it is having an impact on the way the immune system -develops as well.”

Devereux said increasing levels of office-based employment and television viewing might have contributed to a fall in the amount of vitamin D obtained from sunlight.