The risk of adverse reproductive and developmental disorders due to occupational pesticide exposure: an overview of current epidemiological evidence

The epidemiological studies presented in this paper refer to the association between agricultural occupation of parents and the incidence of infertility, congenital malformations, miscarriage, low birthweight, small-for-gestational-age (SGA) birth, preterm delivery and stillbirth. The results of the analyses showed that employment in agriculture increases the risk of specific morphological abnormalities in sperm, including the decreased sperm count per ejaculate and declined percentage of viable sperm. In general, no effect of exposure to pesticides on sexual hormones was observed. The data on the effect of employment in agriculture on the time to pregnancy are unequivocal, but most of them suggest that there is a relationship between the decreased fecundability ratio and pesticide exposure. Nor does the research on the sex ratio of offspring provide explicit results. The analyses indicate that parental employment in agriculture could increase the risk of congenital malformations in the offsprings, particularly such as orofacial cleft, birthmarks in the form of hemangioma as well as musculoskeletal and nervous system defects. The data on the effect of occupational exposure to pesticides on birthweight are inconsistent. Although most of epidemiological studies do not reveal a significantly increased risk of SGA, a slower pace of fetal development corresponding to SGA in the population of women exposed to pyrethroids has been recently reported. There are also some indications that exposure to pesticides may contribute to stillbirth and female infertility. The literature review suggests a great need to increase awareness of workers who are occupationally exposed to pesticides about their potential negative influence on fertility and pregnancy outcome. In the light of existing although still limited evidence of adverse effects of pesticide exposure on fertility during the preconceptual period, it is necessary to reduce the exposure to pesticides.