Birth Defects

There are conflicting studies of the associations of agricultural work and pesticide exposure with birth defects. As in most studies examining reproductive outcomes and pesticide exposure, incomplete data are available on the types of pesticides associated with these defects and biomarkers of exposure. One large study of the Norway birth registry from 1967 to 1991 found activities involving high pesticide exposure and conception during times of high pesticide use (April to June) were associated with an increased risk of central nervous system defects, neural tube defects, limb reductions, and the genitourinary birth defects of hypospadias and cryptorchidism. Some studies have supported these findings while others have found risk estimates close to unity. Other studies have found an association with oral clefts and agriculture work. One difficulty in these studies is that the number of birth defects reported is very small and must be pooled for statistical power. Most of the studies on the risk of birth defects for paternal occupational exposures to pesticides do not find any associations or only small increased risks (31,34-40).

In Spain, maternal pesticide exposure during the first trimester was associated with an increased risk of central nervous system defects and oral clefts. Conventional pesticide use in the Phillipines was associated with increased risk of birth defects compared to low pesticide use (29,41).

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