Risk of birth defects higher when pregnant women exposed to solvents at work.

Dec 11, 2012

Cordier, S, R Garlantézec, L Labat, F Rouget, C Monfort, N Bonvallot, B Roig, J Pulkkinen, C Chevrier and L Multigner. 2012. Exposure during pregnancy to glycol ethers and chlorinated solvents and the risk of congenital malformations. Epidemiology http://dx.doi.org/10.1097/EDE.0b013e31826c2bd8.



Synopsis by Cheryl Stein and Wendy Hessler

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fatedsnowfox/flickr
 
A study of pregnant women in France found that on-the-job exposure to chemical solvents during pregnancy increased the risk of certain types of birth defects. Mothers with more exposure were 4 to 12 times more likely to have babies with oral clefts than mothers with less exposure. Metabolites of two large classes of organic solvents -- glycol ethers and chlorinated solvents -- were linked to occupational use of cleaners and cosmetics in jobs such as hairdressers, chemists and nurses.
 
 

Context

Organic solvents are a large class of chemical compounds with numerous commercial applications. The liquids are important and valuable to industry because they dissolve other substances and evaporate quickly.

Solvents are widely used and may be found in paints, adhesives, glues, coatings and degreasing/cleaning agents. They also are used to produce dyes, polymers, plastics, textiles, printing inks, agricultural products and pharmaceuticals.

The broad use of solvents means people may be exposed at home, school and work. The chemicals can be breathed in or absorbed through the skin. On-the-job exposures occur in several occupations dominated by women, in particular nurses, cleaners, hairdressers and beauticians.

There are thousands of different birth defects. The most common are heart defects, oral clefts, and neural tube defects, such as spina bifida. These changes to the structure or function of the body can affect health and development, according to the March of Dimes.

Some solvents cause birth defects in animals. Several – but not all – studies with pregnant women have shown increased risk of birth defects with occupational exposure to solvents. These human studies, however, mainly determined exposure after the baby was born and did not identify the specific chemicals involved.

What did they do?

This case-control study enrolled pregnant women in Brittanny, France, from 2002 - 2006. The women enrolled by the middle of their second trimester before they knew whether or not the baby had a birth defect. There were 79 birth defect cases and 580 non-birth defect controls.

The women were asked about their contact with 11 classes of products containing certain solvents from work, home or hobbies and about their occupation. They also provided a urine sample that was tested for 10 metabolites of glycol ethers and chlorinated solvents, two widely used classes of solvents. The authors assessed exposures three ways: self-reported by the women, based on the tasks the women performed at work and measured in the urine samples.

Information about birth defects was gathered from birth and hospital records. Tobacco and alcohol use, education, folic acid supplements and other health and life style issues were taken into account during the analysis.

What did they find?

Regular exposure to solvents at work was self-reported by 29 percent of the women. Based on job duties, 21 percent of women were classified as exposed. The occupations with the most regular exposure to solvents were cleaners, nurses, nurse aides, hairdressers and chemists/biologists.

Using either self-report or job classification, the more a pregnant women was exposed to solvents the more likely it was that her baby would have certain birth defects.

Women who reported regular exposure to solvents were four times more likely to have a baby with an oral cleft as compared to women who did not report regular exposure. Using job classifications, exposed women were 12 times more likely to have a baby with an oral cleft as compared to unexposed women. Pregnant women with detectable levels of the solvent ethoxy ethoxyacetic acid, or EEAA, in their urine were 11 times more likely to have a baby with an oral cleft as compared to women without detectable levels of EEAA in their urine. EEAA is a metabolite of glycol ethers used in biocides, cleaning agents and alcohol-based products.

Based on self-report and job classifications there also were increased risks for urinary tract defects and male genital malformations among more highly exposed women.

What does it mean?

Pregnant women with regular exposure to solvents at work were more likely to have a baby born with an oral cleft birth defect than pregnant women without regular exposure to chemical solvents. The relationship between solvents and oral cleft was found when exposures were self-reported by the women, determined by their job tasks or measured in urine.

This study is among the first to measure solvent levels in urine from pregnant women and examine the association between solvent exposure and birth defects. The study addressed two weaknesses of past research by assessing exposure before any birth defects were diagnosed and by measuring solvent metabolites in urine.

The results suggest that exposure to some solvents increases the risk of certain birth defects. The study findings are limited, however, by the small number of cases of specific types of birth defects. For instance, while there are a total of 79 birth defects, there are only eight cases of oral cleft.

Because of the small sample size more study is needed to confirm the finding.

In the United States, about 1 in every 33 babies is born with a birth defect. Birth defects are the leading cause of infant death. Babies born with birth defects have a greater chance of illness or disability than babies born without birth defects.

Not all birth defects can be prevented. Some things women can do to reduce the risk are to take folic acid every day, starting at least one month before getting pregnant; don’t drink alcohol, smoke, or use illicit drugs; talk to a health care provider about taking any medications, including herbal supplements; avoid infections; and be sure any medical conditions, such as diabetes and obesity, are under control before becoming pregnant.

Resources

Birth defects: what they are and how they happen. March of Dimes.

Facts about birth defects. Centers for Disease Control and Prevention.

Organic solvents. Centers for Disease Control and Prevention.

Solvents: workplace standards. Occupational Safety and Health Administration.

 

 

 

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