Discoveries and Data: Specific Conditions

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aortic artery/valve defects
conotruncal heart defects
folic acid
tetralogy of Fallot
pulmonary artery/valve defects
ventricular septal defect

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MULTIVITAMINS WITH FOLIC ACID LOWER RISK BY A THIRD

	Women taking folic acid-containing multivitamins around the time of conception or in early pregnancy had 30% less chance of conotruncal heart defects. The risk reduction did not depend on demographic factors such as mother's age, race/ethnicity or education level.

	One bowl of vitamin-fortified cereal contains at least 0.1 milligrams of folic acid—25% of the daily level recommended for women of childbearing age. Among women who did not take multivitamins, those consuming fortified cereal had lower risks.

	The reduced risk seen in mothers who used multivitamins was mainly in one defect—tetralogy of Fallot—with less reduction in other types of conotruncal abnormalities.

MANY OTHER EXPOSURES STUDIED

	Air pollution. Using detailed air quality surveillance records, researchers found higher levels of 2 pollutants during the second month of pregnancy increased risk for specific heart defects: carbon monoxide was linked to ventricular septal defects and ozone was linked to conotruncal heart defects, pulmonary artery/valve defects and aortic artery/valve defects.

	Corticosteroids. Use of drugs such as cortisone and prednisone used to treat asthma, autoimmune diseases and to reduce inflammation did not alter risk for conotruncal heart defects.

	Drinking water. A possible relationship between drinking contaminated tapwater and heart defects was noted, but intense publicity about water contamination may have influenced mothers' responses. A follow-up study determined neither chlorine (added to water as a disinfectant) nor trihalomethanes (a disinfectant by-product) was responsible for the higher risks, whether exposure came through drinking or bathing/showering.

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	Hazardous waste sites. Women who lived within 1/4 mile of a Superfund site during the first 3 months of pregnancy had a 4 times greater risk of having babies with conotruncal heart defects (increasing from 1/1000 to 1/250 babies.) (English Spanish)

	Pesticides. Household gardening caused a modest risk increase in some types of heart defects. However, we saw no increased risk among mothers with pesticide exposures we had expected to be most intense: occupational contact and self-applied home pest control.

	Smoking. There is a modest risk increase for conotruncal heart defects if both parents smoke. This may be due to other behaviors more common among smokers rather than a direct effect of cigarettes.

	Solvents. Mothers of babies with serious heart defects were 80% more likely to have solvent exposure in the workplace, based on interview reports of occupation and job tasks.

	Stress. Stressful life events—divorce, job loss or death of someone close—were reported 30% to 50% more commonly by mothers of infants with conotruncal heart defects.

	Vitamin A. High doses of vitamin A induce birth defects in laboratory animals; however, we found no higher risk for heart defects among mothers who took vitamin A supplements during pregnancy.