The Seychelles child development study on neurodevelopmental outcomes in children following in utero exposure to methylmercury from a maternal fish diet: background and demographics.

Studies in Japan showed that fetal exposure to methylmercury during pregnancy can lead to severe neurodevelopmental changes in the infant while the mother suffers no or minimal effects. Fish contains methylmercury and there is concern that adverse neurodevelopmental effects may occur secondary to low-dose methylmercury exposure in utero from maternal fish consumption. The Seychelles Child Development Study has been examining the relationship between prenatal exposure to methylmercury during pregnancy in a population with high fish consumption and the neurodevelopmental outcome. Over 80% of Seychellois women eat fish daily, and the median fish meals per week during pregnancy is 12. Following a pilot study of 804 mother-infant pairs, a longitudinal main study of another 779 mother-infant pairs was initiated. The main study design includes collection of educational and socioeconomic information about the family and periodic standardized neurodevelopmental tests at specific ages from 6 1/2 months to 66 months of age. In this paper, we describe the background to the studies and give demographic characteristics of both the pilot and main study cohorts.