WEDNESDAY, Oct. 6, 2004 (HealthDayNews) -- Children of women exposed to organic solvents at their jobs while pregnant run the risk of subtle cognitive and learning problems, a new study says.
This is true even in workplaces where precautions are taken against exposure to the solvents that include toluene, which is used in nail polish remover, and xylene, which is found in paints and varnishes, the researchers said.
The women had jobs ranging from a hair stylist, to a graphic designer, to a carpenter, to a science teacher. All their work settings had safety measures designed to reduce exposure to the chemicals. The precautions included laminar flows -- hooded machines that suck the toxins from the air -- and face masks that filter the air during breathing. All the women reported using the protective devices when they worked, the University of Toronto researchers said.
"These were not women working in small sweatshops, but mostly in places under supervision," said study author Dr. Gideon Koren, director of the Motherisk Program at the University of Toronto.
They were exposed to the chemicals throughout their pregnancy for an average of four hours a day, he said.
One women's health expert, cautioned, however, that the vast majority of the 3 million American women who become pregnant each year don't experience the level of exposure seen in the women in this study.
The researchers compared the cognitive, language and motor skills of 32 children born to mothers who had been exposed to organic solvents during pregnancy to children whose mothers worked in places that didn't have such solvents. They found subtle but statistically significant differences in the children's performances on standardized tests measuring "short-term auditory memory, general verbal information and attention," the scientists said.
"All these kids were perceived by their parents to be OK, but these were more subtle differences," Koren said.
For instance, children born to mothers who'd been exposed to solvents "tended to be somewhat more hyperactive. We wouldn't qualify them as hyperactive, but under stress, hyperactivity could be a problem," he said.
And in tests to assess memory -- including recalling pictures on cards -- the children of mothers who had been exposed to the solvents did not score as well as children in the control group.
The study appears in the October issue of the Archives of Pediatrics and Adolescent Medicine.
Organic solvents are chemicals used to dissolve organic compounds. Toluene and xylene were two of most common solvents to which the women were exposed. In all, 78 solvents were tested, the researchers said.
One explanation for the findings, Koren said, is that "the rules now of what is safe in the workplace are based on adults."
Dr. Philip J. Landrigan, professor and chairman of the Department of Community & Preventive Medicine at Mount Sinai School of Medicine in New York City, agreed that new guidelines may be needed to protect the health of unborn babies.
With lead, for instance, "a level of over 5 or 10 micrograms of lead in the blood is sufficient to cause degrees of fetal brain injury, yet it is legal to have a blood level of 40 micrograms of lead in people in the workplace," he said. "This fails to protect the baby that the pregnant mom brings to work."
However, Dr. Daniel Saltzman, a New York City obstetrician-gynecologist who specializes in high-risk pregnancies, said the vast majority of the 3 million U.S. women who become pregnant each year don't experience the high level of exposure experienced by the women in the study.
"The key point is the dosing and duration of exposure," he said. "I'm concerned that people will say, 'I'm afraid I'm going to damage my baby if I have any exposure at all."
The study researchers accounted for variables such as maternal IQ and maternal education. The children in both groups ranged in age from 3 to 9 years. There were no differences in birth weight, gestational age or age at achieving certain behavioral milestones, and none had major malformations or neurological problems, the researchers said.
Koren said pregnant women who work in places where organic solvents are used should take steps to limit their exposure.
"We agonized about the ramifications of this, and I don't believe that women have to leave their work," he said. "But they should look much more carefully at their workplace and should review each step of their work routine."
This includes paying prompt attention to any symptoms such as a runny nose or eyes, a cough or headache. Pregnant women also should consider moving to another part of the workplace to reduce their exposure to the solvents, Koren said.
To learn more about workplace hazards for pregnant women, you can visit the National Institute for Occupational Safety and Health.