Doctors at Southampton General Hospital have found that mothers can influence whether their babies develop sensitisation to allergies. It is estimated that one child in seven suffers from asthma and allergies, double the number 10 years ago. Environmental pollution, diet and central heating have all been blamed.
Dr Jill Warner, who led the Southampton team, said: "Controlling the mothers' reactions to allergens, especially during the second and third trimester of pregnancy [from the fourth month onwards] may well be the treatment of the future, alongside established advice such as giving up smoking and cutting down on alcohol."
The team analysed bloodfrom 100 children aged up to five. They found that by 22 weeks of gestation babies were able to recognise common allergens such as dust mites.
"We studied blood samples from premature babies to determine their immune response to common allergens such as household dust and grass pollen and found that babies who later became allergic reacted more strongly to allergens than those who had no disease," she said.
The researchers found the most important predictor of asthma at age five is the number of positive allergy tests at the age of one. This gives parents the chance to avoid the allergens that could later trigger asthma, Dr Warner said.
The team has shown that allergy avoidance regimes, using dehumidifiers and high- efficiency vacuum cleaners, are important in preventing allergy and asthma in babies.