These findings, Dr. Petra Arck told Reuters Health
in an email, could "allow clinicians to evaluate future asthma risk
in unborn children using a simple life event assessment
Arck, of University Medical Center Hamburg-Eppendorf in Germany, and
her colleagues note that although there are strong genetic
components to asthma and related conditions, these alone do not help
explain the unprecedented increase in such diseases in recent years.
Over the same period as that increase, they add, stress levels have
been on the rise. But there hasn't been much evidence to connect
stress in pregnancy to asthma and eczema.
To investigate further, the researchers examined data from 1,587
children and their mothers who took part in an Australian pregnancy
study. The original purpose of the study was to determine the
effects of intensive fetal monitoring on pregnancy outcomes.
Mothers-to-be were asked about recent stressful life events halfway
through their pregnancy and again toward the end of pregnancy. Their
children were evaluated for asthma, eczema and other allergy-related
conditions at age 6 and 14.
Complete data were available for 994 children and their mothers.
The researchers calculated that the likelihood of having asthma or
eczema as a teenager was substantially higher among children of
mothers who experienced stressful life events during the second half
of their pregnancies.
Specifically, kids were about twice as likely to have asthma as
14-year-olds if their mothers had been through a single stressful
life event, once other factors known to influence asthma were taken
into account. Risks were similar when mothers had experienced
multiple life stressors.
When the researchers looked
closer, they found that pattern only held among children whose
mothers did not have asthma themselves.
There was no link between stressful events in pregnancy and a
child's chance of having asthma or eczema at age six, according to
findings published in the Journal of Allergy and Clinical
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The authors note that they did not have information on how
mothers-to-be coped with stressful life events or the types of
social support they had available.
And they point out that factors other than stress in pregnancy might
have been responsible for the increased risk of disease in certain
One researcher not involved in the study said it was well designed
and addressed an important topic, but urged caution when
interpreting the findings.
Alet H. Wijga, from the National Institute for Public Health and the
Environment in Bilthoven, the Netherlands, echoed the warning that
stress, itself, may not have been what caused kids' asthma and
"Life events like money problems, job loss and residential move
associated with separation or divorce during pregnancy may well have
lasting impact on the socio-economic position of the mother and her
child and may, for example, be associated with unfavorable indoor
and outdoor exposures throughout the child's life course up to
adolescence," Wijga told Reuters Health in an email.
"I do think the study provides evidence for an association between
prenatal adverse life events and the risk for allergic disease in
childhood," Wijga said. The challenge in the future will be to sort
out the possible effects of stress during pregnancy from a child's
environment growing up, the researcher added.
Journal of Allergy and Clinical
Immunology, online March 24, 2014.
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