Stressed pregnant women are more likely to have children with allergies

Pregnancy stress is linked to allergies

Findings from a U.S. study suggest babies exposed to stress before birth have an increased tendency to react to allergy triggers such as dust mites.

It is thought the developing immune system of unborn babies can be changed by maternal stress, probably through stress hormones such as cortisol.

The results of the study, at Harvard Medical School, Boston, were presented yesterday at the American Thoracic Society International Conference in Toronto.

They held true regardless of the mother's race, class, education or smoking history. Lead researcher Dr Rosalind Wright, of Brigham & Women's Hospital and Harvard Medical School, said: "While predisposition to asthma may be, in part, set at birth, the factors that may determine this are not strictly genetic.

"This research supports the notion that stress can be thought of as a social pollutant that, when 'breathed' into the body, may influence the immune response, similar to the effects of physical pollutants like allergens."

Previous research has found children of stressed mothers had lower IQs at 18 months and double the risk of hyperactivity and attention deficit hyperactivity disorder at the age of four.

There are 5.2million asthma sufferers in the UK, including 1.1million children, while growing numbers of children suffer from allergies.