Reduced blood supply to the developing abdominal wall is thought to cause gastroschisis, a life-threatening condition where the intestines protrude from a hole near the umbilical cord. In interviews, mothers were asked about work activities as well as hobbies during pregnancy. An industrial hygienist evaluated the exposures that might be associated with each occupation/hobby.

	Several hobbies—ranging from automechanics to weaving—were associated with gastroschisis. All but 2 involved the use of solvents or colorants (dyes).
	High-level exposure to solvents raised risk by nearly 4 times; low-level exposure raised risk about 2 times.
	Women had a greater risk when exposure to solvents came through hobby-related activities such as automechanics, furniture stripping and painting.
	Secondhand exposure to solvents—through activities of another person in the household—did not increase the risk for gastroschisis.
	Exposure to all classes of solvents raised risk: aromatic hydrocarbons (benzene, toluene), aliphatic hydrocarbons (propane, some aerosol propellants), glycols (ethylene glycol, antifreeze) and isopropyl alcohol (rubbing alcohol).
	Mothers exposed to colorants—pigments, metallic and organic dyes—had double the risk. Colored wall or furniture paints, fabric dyes/paint, permanent hair dye, nail polish and corroded metal all contain colorants.

SANTA CLARA COUNTY WATER STUDIES

Several early Program studies looked at heart defects following discovery of drinking water contaminated with the solvents trichloroethane and dichloroethylene in Santa Clara County.

	A possible relationship between drinking tapwater and heart defects was noted countywide (beyond the area of known contamination). However, there were many potential sources of bias in the study—interviews were conducted 3-7 years after birth; intense publicity about water contamination may have influenced mothers' responses.
	Mothers of babies with serious heart defects were more likely to have solvent exposure in the workplace, based on interview reports of occupation and job tasks.

NO INCREASED RISK FOR NEURAL TUBE DEFECTS

We asked women about occupational or hobby chemical exposures; an industrial hygienist assessed exposure based on specific tasks. Exposure to organic solvents or 74 chemicals groups did not raise risk for having neural tube defects.