Review of neural tube defects: risk factors in parental occupation and the environment.

We conducted a study of published work to evaluate the evidence for the hypothesis that environmental exposure and parental occupation are risk factors for neural tube defects. As other risk factors such as maternal illnesses, medication, and dietary factors have been reviewed before, this review only summarizes this information. In studies concerning environmental pollution, only a few weak associations were found. It appears that specific studies on the topic of parental occupation and neural tube defects are scarce. Therefore, studies on broader malformation categories, such as central nervous system defects, were also taken into account. Both maternal and paternal occupation seem to be associated with the occurrence of neural tube defects. However, results are not always consistent with each other, and relevant recommendations concerning prevention thus cannot be given before more studies with larger populations are conducted to confirm or refute the findings reviewed.