MONDAY, Feb. 7 (HealthDay News) -- Children whose mothers had
higher levels of exposure to a substance found in a commonly used
pesticide were more likely to get lower scores on a mental
developmental test at 3 years of age than children whose mothers
were exposed to lower levels or not at all, new research says.
Megan Horton, a postdoctoral research fellow at Columbia
University's Mailman School of Public Health in New York City, and
her colleagues followed 348 mothers from low-income areas of New
York City whose prenatal exposure to pyrethroid insecticides --
found in pesticides commonly used around the home -- was
The researchers measured not the common pyrethroid called
permethrin but rather piperonyl butoxide (PBO), a chemical added to
permethrin that boosts its potency, Horton said. They measured PBO
because permethrin is metabolized quickly and difficult to measure,
The study authors measured the mothers' prenatal exposure by
taking air samples or blood samples. To get the air samples,
mothers wore backpacks that collected air from their breathing
zone, which was then analyzed.
Children were then put into four groups or "quartiles,"
depending on the level of their mothers' exposures to PBO during
At age 3, the children were evaluated using standard scales to
assess their cognitive and motor development, according to the
study published online Feb. 7 in the journal
"Kids who were in the highest quartile range of exposure to PBO were three times as likely to be in the delayed category, compared to kids with lower exposure," Horton said.
Horton's team compensated for factors such as gender, ethnicity,
education of the mothers, and toxins such as tobacco smoke in the
Horton said it's impossible to say what levels of pesticide are
safe, partly because many factors come into play, such as the type
of pesticide used and the ventilation provided.
She did not have data on the frequency of pesticide use. "I
don't know whether the mothers used it five times a week or once a
week," she added.
Pyrethroid insecticides have replaced another class of bug
killers, known as organophosphorus (OP) insecticides, Horton said.
Increasing pesticide regulations from the U.S. Environmental
Protection Agency have resulted in fewer residential exposures to
OP insecticides, she said.
But, pyrethroid insecticides have not been evaluated for
long-term effects on the body after low-level exposure, she
Jennifer Sass, a senior scientist at the Natural Resources
Defense Council, who reviewed the study but was not involved with
it, said the findings ''should convince every parent and want-to-be
parent to avoid these pesticides."
Horton suggests that parents turn to so-called integrated pest
management, which includes common-sense measures to control pests
such as eating only in home eating areas, not bedrooms; keeping
cracks and crevices in the house repaired to keep out pests; using
trash cans with a lid and liner to contain garbage; and storing
HealthDay to reach the pesticide industry for comment were
To learn more about integrated pest management, visit the
U.S. Environmental Protection Agency.