The children had lower IQs, poorer language and memory skills, and were inattentive and hyperactive, researchers at the Hospital for Sick Children found. "It does seem that organic solvents do affect brain development when exposure occurs in pregnancy, which means women should do everything possible to minimize such exposure," said Gideon Koren, director of the Motherisk program at Sick Kids and the lead investigator.
The research, published in the medical journal Archives of Pediatric and Adolescent Medicine, looked at 32 women who were exposed to organic solvents in the workplace for at least eight weeks of pregnancy, along with their children, who were aged 3 to 9 at the time of testing. They were compared to 32 women of similar background who did not work in jobs where solvents were used, and their children.
The women in the study worked in 17 different occupations, including painter, science teacher, photo-lab worker, graphic designer, electrical-company workers and embalmer.
All told, they reported being exposed to at least 78 different chemicals in the workplace, although all said they used protective equipment such as masks and gloves to minimize their exposure to the chemicals. Their average time of exposure was 28 weeks.
Organic solvents are used in a number of industrial processes and found in a host of products, such as paints, inks, embalming fluids and beauty products.
Manu Barrera, an associate professor of applied psychology at the University of Toronto and a co-author of the study, said the differences between those exposed in utero to the solvents and their peers were small but nonetheless significant.
While none of the mothers reported major problems with their children, she said testing showed some definite delays. "We found that the children of the exposed women had significantly lower verbal cognitive functioning . . . we also saw greater inattention and hyperactivity in the exposed children," Dr. Barrera said.
While the differences were "subtle," the researchers said the study is important because it is the first to document possible harm to a fetus from exposure to organic solvents.
Earlier research has shown damage to the brains of adult "sniffers" and to the offspring of laboratory animals.
Dr. Koren said the study did not try to determine a dose-response -- how much or what kind of exposure caused the most damage. "Studies designed to clarify exposure effects in regard to specific solvents, dose levels, and timing of exposure will be most valuable," Dr. Koren said.
Workplace safety legislation differs from province to province, and rules governing exposure to solvents can change from one workplace to the next.
Dr. Koren said that the problem is that workplace exposure to toxic chemicals usually deals with protecting adults, and in-utero exposure is rarely considered.
"The adult may be okay, but the unborn's brain is much more sensitive. It's still developing," he said. "The baby needs his own guidelines."
Studies have shown that adults who breathe in fumes or absorb solvents through the skin can suffer neurological dysfunction, from lowered IQ to lack of co-ordination to vision problems -- including the loss of colour recognition.
"Clearly, these effects are very well known in the adult working there, day in and day out. But the question was . . . The baby's exposed to it day in, day out, too. What will happen to the baby?" Dr. Koren said.
