Residing near a farm that uses the pesticide atrazine could accentuate the risk of gastroschisis, a rare birth defect, according to a study presented last Friday at the annual meeting of the Society for Maternal-Fetal Medicine in Chicago, reports Reuters Health.

Gastroschisis, a condition when part of the intestines bulges through a separation in the stomach, affects approximately 1 in 5000 children born in the U.S. each year, says the March of Dimes. This rate has increased 2- to 4-fold over the last three decades, according to Dr. Sarah Waller, of the University of Washington, Seattle.

Waller’s researchers were drawn to the potential connection between atrazine and the birth defect because, as they state in their conference abstract, “during the last 10 years, the highest percentage per population of gastroschisis was in Yakima County, in the eastern part of the state, where agriculture is the primary industry,” said Reuters Health.

“Our state has about two times the national average number of cases of gastroschisis,” said Dr.Waller, quoted Science Daily. “The life expectancy for fetuses with this diagnosis is better than 90 percent; however it requires delivery at a tertiary care center with immediate neonatal intervention which often separates families and can cause serious financial and emotional stress.”

The study entailed more than 4,400 birth certificates from 1987-2006, comprising more than 800 cases of gastroschisis, and databases of agricultural spraying between 2001 and 2006 from the U.S. Geological Survey.

Based on Environmental Protection Agency (EPA) standards for high chemical exposure levels in surface water, the team discovered that if a mother lived near a site of atrazine high surface water contamination, she was likelier to deliver a baby with gastroschisis.

The birth defect was more prevalent among infants who lived less than 15 miles from a site, and  occurred more often among babies conceived between March and May, the usual time for agricultural spraying.

According to a press statement by atrazine’s maker, Syngenta, studies designed like Waller’s “make broad generalizations about environmental conditions and often overlook” factors that might affect the rate of a given condition, reports Reuters Health.

The study, said Syngenta, “provides no direct or credible link between atrazine and the kind of birth defect, gastroschisis, which it examined.”

“Through thousands of studies, atrazine has been found again and again to not cause any variety of health effects, including those in this Washington study,” Syngenta spokesman Steven Goldsmith said. “Use of atrazine in Washington state is the second lowest amount in the country, and in eastern Washington, so little is used that it barely appears in surface water.”

But Dr. Waller’s group is not the first to report an association between gastroschisis-like birth defects and surface water atrazine levels. Last fall, the Environmental Protection Agency (EPA) announced it was re-evaluating health outcomes linked to atrazine discovered in drinking water, said the Associated Press (AP) previously. The AP noted that, based on findings, rainstorm run-off can contaminate streams, rivers, and water systems; also, new research indicates that even at lower levels, atrazine in drinking water can cause “low birth weights, birth defects and reproductive problems,” said the AP.

Pesticides of any kind pose risks, especially for children and those with compromised immune systems. Another study linked pediatric cancer to household pesticides. That investigation revealed the relatedness occurred in children with acute lymphoblastic leukemia (ALL), a cancer that usually develops in children between three and seven years of age, said ScienceDaily, previously.