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Stress in pregnancy may raise asthma risk

High stress levels during pregnancy might raise children’s asthma risk

OnMedica staff

Thursday, 18 March 2010

Babies of women who experience high levels of stress during pregnancy may be more likely to go on to develop asthma, a study from the US has shown.

Animal studies had already shown that maternal stress prenatally could affect their offspring’s immune system, and researchers wanted to know if this could help explain why communities in disadvantaged inner-city areas have a higher prevalence of asthma –even once physical factors are allowed for.

Pregnant women from several cities in the US joined this study. These women, from 557 families, were mostly from ethnic minorities; 20% were living below the poverty line; and in all cases they or the baby’s father had a history of asthma or allergy. They answered detailed questions about their experience of stress in their lives, for example domestic violence, violence in their neighbourhoods and financial problems.

The babies’ cord blood was collected at birth, and immune cells isolated from this blood were stimulated with common allergens.

Researchers found that the immune cells’ production of various cytokines in response to stimulation varied according to the level of stress than their mothers had experienced during pregnancy.

"The cytokine patterns seen in the higher stress groups, which are an indication of how the child’s immune system is functioning at birth, may be a marker of increased risk for developing asthma and allergy as they get older,” said lead researcher Rosalind Wright, from Brigham and Women’s Hospital in Boston.

"For example, while the debate continues as to whether primary sensitisation to allergens begins before birth, these findings suggest the possibility that prenatal stress may enhance the neonate’s response to inhalant antigens, specifically those antigens that the fetus is likely to encounter more directly in utero, like dust mite."

The prospective cohort study will continue as the infants grow up, to determine whether maternal stress levels do indeed have an impact on asthma development.

"The current findings suggest that psychological stress is involved in programming of the infant immune response and that this influence begins during pregnancy," said Dr. Wright. "As these infants mature, we will learn how these factors manifest later in terms of the development of asthma and allergy."

The findings have been published online this week, ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

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