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ENS: Residence near sprayed pesticides linked to miscarriage

Gary Greenberg Gary.Greenberg at Duke.edu
Tue Feb 20 01:21:27 EST 2001

Pesticide Exposure Could Boost Risk of Miscarriage

Please visit the website for the whole story.
Abstract for the actual study is below.

By Cat Lazaroff

CHAPEL HILL, North Carolina, February 19, 2001 (ENS) - Living close to
areas where agricultural pesticides are applied may boost the risk of
fetal death due to birth defects, a new University of North Carolina at
Chapel Hill study indicates. Researchers say their findings suggest but
do not prove a hazard from pesticide exposure. 

The study, which involved almost 700 women in 10 California counties,
showed an increased risk of death among developing babies. Mothers who
lived near crops where certain pesticides were sprayed faced a 40 to 120
percent increase in risk of miscarriage due to birth defects. 


Five pesticide classes were examined in the new study, including
phosphates, pyrethroids, halogenated hydrocarbons, carbamates and
endocrine disruptors. 

Scientists compared the cases of 73 women whose pregnancies ended
because of birth defects with 611 control subjects whose pregnancies
ended in normal live births. 

"Our study showed a consistent pattern with respect to timing of
exposure," said Dr. Erin Bell, who earned her doctorate with the
research at the University of North Carolina (UNC) School of Public
Health. "The largest risks for fetal death due to birth defects were
from pesticide exposure during the third week to the eighth week of

That span - much of the first trimester - appears to be a special window
of vulnerability for birth defects, Bell said, just as earlier research
has suggested. 


"The risks appeared to be strongest among pregnant women who lived in
the same square mile where pesticides were used," she said. 

A report on the research will appear in the March issue of
"Epidemiology," a public health journal. Besides Bell, now an
epidemiologist with the National Cancer Institute, the authors include
her mentor Dr. Irva Hertz-Picciotto, professor of epidemiology at UNC,
and Dr. James Beaumont, formerly of the University of California at
Davis and now with the California Environmental Protection Agency. 


Investigators cautioned that further study is needed since they lacked
certain information. 

"Our exposure classification method did not guarantee that a mother was
in fact exposed because wind and weather conditions, hour of application
and the location of the mother at the times of application were all
factors that would determine actual exposure," she said. 


In the past, few epidemiological studies of pesticide exposure and birth
defects have considered timing of possible exposures. California
counties included in the new UNC study were Madera, Tulare, Kings,
Merced, Monterey, Stanislaus, San Joaquin, Riverside, Fresno and Kern. 

= - = - = - = - = - = - = - = - = - = - = - = 

A Case-Control Study of Pesticides and Fetal Death Due to Congenital

Erin M. Bell, Irva Hertz-Picciotto, and James J. Beaumont 


We examined the association between late fetal death due to congenital
anomalies (73 cases, 611 controls) and maternal residential proximity to
pesticide applications in ten California counties. A statewide database
of all applications of restricted pesticides was linked to maternal
address to determine daily exposure status. We examined five pesticide
chemical classes. The odds ratios from logistic regression models,
adjusted for maternal age and county, showed a consistent pattern with
respect to timing of exposure; the largest risks for fetal death due to
congenital anomalies were from pesticide exposure during the 3rd-8th
weeks of pregnancy. For exposure either in the square mile of the
maternal residence or in one of the adjacent 8 square miles, odds ratios
ranged from 1.4 (95% confidence interval = 0.8-2.4) for phosphates,
carbamates, and endocrine disruptors to 2.2 (95% confidence interval =
1.3-3.9) for halogenated hydrocarbons. Similar odds ratios were observed
when a more restrictive definition of nonexposure (not exposed to any of
the five pesticide classes during the 3rd-8th weeks of pregnancy) was
used. The odds ratios for all pesticide classes increased when exposure
occurred within the same square mile of maternal residence. 

Keywords: fetal death, pesticides, congenital anomalies, phosphates,
pyrethroids, halogenated hydrocarbons, carbamates, endocrine disruptors. 

Gary N. Greenberg, MD MPH    Sysop / Moderator Occ-Env-Med-L MailList
gary.greenberg at duke.edu     Duke Occupat, Environ, Int & Fam Medicine
OEM-L Maillist Website:                      http://occhealthnews.com


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