Maternal exposure to weed rodent killers raises risk of congenital heart defect.

Data analysis of a case-control study conducted from 1981 to 1989 reveals that early maternal exposure to rodenticides and herbicides quintuples and triples the risk of having an infant with congenital heart disease respectively. The analysis included 1832 infants with congenital heart defects and 771 infants without such defects who were born in the Baltimore- Washington DC area in 1987-89 and treated at one of the regions six pediatric cardiology centers. Interviews were conducted among childrens parents to obtain information on socioeconomic and demographic status family history of heart defects and parental exposure to environmental contaminants. Preliminary analysis indicated that heart defects as a group were not associated with pesticide exposure. However a malformation called transposition of the great arteries was noted. In addition the families of infants with transposed arteries were of lower social economic status than that of the controls. Also their parents were more likely to have been exposed to solvents and pesticides. On the other hand no overall trend was evident according to frequency of exposure. Furthermore the timing of pesticide exposure in relation to conception was associated with the risk of having an infant with transposed arteries.