Children born to mothers who were exposed to organic solvents at their workplace during pregnancy are more likely to have a heart defect at birth, say researchers.

The study, published in Occupational and Environmental Medicine, evaluated the levels of workplace exposure to organic solvents in 5,000 women from across the United States from one month before conception through to the first three months of pregnancy.

All the women were participating in the National Birth Defects Prevention Study.

All of their babies were born between 1997 and 2002. Researchers also included data on stillbirths and abortions.

Organic solvents, found in varnishes, paints, degreasing/cleaning agents, adhesives, dyes, plastic, polymers, printing inks, synthetic textiles, and agricultural products, are extensively used in chemical manufacturing as well as for dissolving or dispersing substances, such as oils, waxes, and fats. The majority of organic solvents are highly dangerous and penetrate the body via the lungs, mouth, and skin.

The team looked for links between exposure to organic solvents which are common in some workplaces, and 15 categories of congenital heart defects.

The solvents examined included chlorinated solvents; aromatic solvents; and a mix of C10 or higher hydrocarbons known as Stoddard solvent.

The team used two different methods to measure level of exposure: an expert consensus-based approach and an approach based on the published evidence.

According to the expert consensus approach approximately 5% of mothers whose babies did have birth defects, and 4% of those who didn’t, were exposed to an organic solvent around the time they were trying to conceive or at the start of their pregnancy.

However, the published evidence approach indicated that these figures were 10% and 8%, respectively.

Two types of heart defects were linked to exposure of any solvent and to chlorinated solvents, according to the expert consensus approach, while the published evidence approach suggested that there were several additional links between congenital heart defects and exposure to organic solvents.

According to the researchers, their study indicates that exposure to organic solvents is a potential risk factor for several types of heart defects at birth.

However, the researchers state that “despite the strengths of this analysis, the results do not allow for the drawing of definitive conclusions on specific exposure-congenital heart defect combinations.”

Written by Grace Rattue