From the Montreal Gaxette, July 31 2008:
Highways affect newborns' health
Affluent women more likely to deliver prematurely: study
JULIA KILPATRICK, The Gazette
Published: 6 hours ago
Pregnant women living near highways on the island of Montreal -
particularly women from affluent neighbourhoods - are more likely to
deliver preterm, low-weight or small babies, researchers say.
The odds of delivering a low-weight infant are 81 per cent higher than
average for expectant mothers living in high-
income neighbourhoods within 200 metres of highways, according to a
report published in the August edition of the Journal of Epidemiology
and Community Heath. Affluent women also are 58 per cent more likely
to deliver early compared with women who don't live near an expressway.
"At the beginning, we thought that low-income mothers would be more
susceptible to pollution from highways, so we were quite surprised,"
said Dr. Mélissa Généreux, lead author of the study. Généreux is a
public health resident at the Université de Montréal-affiliated
Maisonneuve-Rosemount Hospital, and she has a hypothesis to explain
the unexpected results.
"Mothers in low-income neighbourhoods are often exposed to other risk
factors during their pregnancies," said Généreux, explaining that
those women are more likely to smoke, have poor nutrition, be exposed
to domestic violence or have less access to prenatal care.
Women from more privileged backgrounds may not have developed as high
a tolerance to toxins, Généreux said, so poor air quality would have a
more profound effect during pregnancy.
The study also found that overall, well-educated, affluent women are
less likely to have problematic pregnancies, but pollution appears to
have a more acute effect on them.
For all women, regardless of social status, living close to a highway
increased the odds of a low-weight birth by 17 per cent and preterm
delivery by 14 per cent.
The results of the study were disconcerting to Caroline Millette, 29,
who lives in a middle-class neighbourhood in Mascouche near the
intersection of Highways 640 and 25. She gave birth to her daughter
Léanne three months ago, almost two years after her firstborn, Camille.
Both girls were born a month prematurely.
"We thought it was a coincidence," Millette said. "I paid careful
attention during my pregnancy. ... If I hadn't taken so many
precautions, maybe my children would have been sick."
In the study, researchers examined data on close to 100,000 live
births recorded from 1997 to 2001 in the Quebec birth registry, which
includes information on mothers' education.
They compared those records to 2001 census data on the proportion of
residents below the low-income threshold to determine the
socioeconomic status of each neighbourhood and individual.
Highways were identified as major roadways with posted speed limits of
at least 70 kilometres per hour, and exposure to highway pollution was
determined by previous studies.
According to Généreux, exposure to pollution during pregnancy may
impair fetus growth as toxins may be absorbed and exchanged through
the placenta. Pollution has also been shown to increase maternal
susceptibility to infection and respiratory problems.
Previous research conducted in Montreal and elsewhere has identified
various illnesses that arise from living too close to the highway or
in areas with low air quality.
A study in Taiwan found a correlation between exposure to pollution
and adverse birth outcomes, while studies in Los Angeles link high
traffic density with increased low-weight and preterm births among
The study, titled "Neighbourhood socioeconomic status, maternal
education and adverse birth outcomes among mothers living near
highways," was a joint project between the Université de Montréal and
the University of South Australia.
Montreal QC Canada
[Non-text portions of this message have been removed]