[humanser] Study in hurricane region reveals effects of stress on pregnancy

[Mary Ann Robinson]

Study in hurricane region reveals effects of stress on pregnancy
Posted June 22, 2012; 03:53 p.m.  by Michael Hotchkiss
  Expectant mothers who dealt with the strain of a hurricane or
major tropical storm passing nearby during their pregnancy had
children who were at elevated risk for abnormal health conditions
at birth, according to a study led by a Princeton University
researcher that offers new insights into the effects of stress on
pregnancy.
  The study used birth records from Texas and meteorological
information to identify children born in the state between 1996
and 2008 whose mothers were in the path of a major tropical storm
or hurricane during pregnancy.  The children's health at birth
was compared with that of siblings whose gestation didn't
coincide with a major weather event.
  The study found that mothers living within 30 kilometers of a
hurricane's path during their third trimester were 60 percent
more likely to have a newborn with abnormal conditions, which are
detailed on birth records.  Those conditions included being on a
ventilator for more than 30 minutes or experiencing meconium
aspiration, which occurs when a newborn breathes in a mixture of
meconium his or early feces his and amniotic fluid around the
time of delivery.  Increased risk was also found following
exposure to weather-related stressors in the first trimester,
while evidence was less clear for exposure in the second
trimester.  The researchers were able to isolate the impact of
stress caused by the storm from other factors, such as changes in
the availability of health care in a storm's aftermath.
  The study breaks ground by homing in on new his and potentially
better his ways to measure the impact of prebirth stress on
newborns and opens avenues for further research into the
potential impact on such children's later development, said lead
researcher Janet Currie Princeton's Henry Putnam Professor of
Economics and Public Affairs at the Woodrow Wilson School of
Public and International Affairs and director of the Center for
Health and Wellbeing.
  "Probably the most important finding of our study is that it
does seem like being subjected to stress in pregnancy has some
negative effect on the baby, but that the effect is more subtle
than some of the previous studies have suggested," said Currie,
who conducted the study along with Maya Rossin-Slater, a doctoral
candidate in the Department of Economics at Columbia University.
  Anna Aizer, associate professor of economics and public policy
at Brown University who wasn't involved in the study, said the
research "really raises the bar in terms of identification of the
effect of stressful events in-utero on birth outcomes."
  "Previous work has not really been able to isolate the effect
as well as Currie and Rossin-Slater have," said Aizer, whose
research focuses on issues related to children's well-being.
  Meconium aspiration his usually a sign of fetal distress his
and other respiratory problems that necessitate a baby being
placed on a ventilator can generally be treated successfully, but
the study offers new paths for future research about the
long-term health of children born in the wake of stressful events
such as hurricanes.
  "I think there's every reason to believe that if you have a
better measure of child health his like you knew this child was
having breathing problems at birth his that might be a stronger
predictor of longer-term outcomes," Currie said.  "There's a lot
of interest in this whole area of how things that happen very
early in life can affect future outcomes."
  Previous research into the impact of similar types of stress
has found changes in length of gestation and birth weight, but
the new study didn't find a significant effect on those measures,
Currie said.
  Currie said one explanation for the difference is that the new
study utilized data that allowed the researchers to control for
changes in the population of an area around the time of a storm
that could have affected the previous findings.  Earlier research
hasn't been able to account for the way the population of an area
changes around the time of a stressful event his with people of
certain demographic groups more likely than others to move away
or stay nearby.
  The new study included data on eight hurricanes and tropical
storms that hit any part of Texas between 1996 and 2008 and
caused more than $10 million damage.  The most damaging storms
were Tropical Storm Allison in 2001, which caused more than $50
billion in damage and 40 deaths, and Hurricane Ike, which caused
$19.3 billion in damage and 103 deaths.
  Experiencing a hurricane or major tropical storm can have a
significant impact on people that goes well beyond stress.
However, Currie said the researchers were able to determine that
findings related to abnormal health conditions at birth generally
weren't tied to disruption of medical care or property damage
caused by the storms, such as damage to an expectant mother's
home that might lead to injury or increased risk of illness.
They also found little consistent evidence that the stress
associated with storms affected mothers' behaviors, such as
smoking, eating as reflected in weight gain and use of prenatal
care.
  One potential cause of the health problems found in the study
is an increase in stress hormones caused by the storm, which
occurred in what is known as the neuroendocrine pathway.
  "I think the takeaway finding is that it's worth doing more
focused research on those pathways and looking for more subtle
effects on the fetus than just looking at birth weight and
preterm delivery," Currie said.  "And it would be really great if
we could follow over time and see what happens to children who
are affected by these types of events."
  Aizer said the research could also have implications beyond the
context of natural disasters.
  "Previous work has shown poor mothers are exposed to more
stressors.  Currie and Rossin-Slater's work suggests that
exposure to stress might be one of the mechanisms explaining why
poor women have worse birth outcomes," Aizer said.  "Policymakers
concerned with improving the outcomes of poor families should
consider these findings."
  The study, which is described in a working paper circulated in
May by the National Bureau of Economic Research, was supported by
funding from the Eunice Kennedy Shriver National Institute of
Child Health and Human Development.