Apparently normal frequency of congenital anomalies in the highly polluted town of Cubatão, Brazil.

Anencephaly is Suspected to cluster in the municipality of Cubatão (Brazil), and is attributed to industrial pollution. We surveyed malformations prospectively in 10,000 births, in 3 consecutive series, corresponding to 3 maternity hospital in Cubatão, under working definitions and norms taken from the ECLAMC (Latin American Collaborative Study of Congenital Malformations). The sample from Cubatão had a higher proportion of black racial ancestry, and lower frequencies for stillbirths and for immediate neonatal death, than in the rest of South America. The birth prevalence of malformations varied between the 3 hospitals in Cubatão, due to differences in ascertainment of minor defects. A higher-than-expected prevalence rate in Cubatão was observed only for postaxial polydactyly, probably due to a higher proportion of black racial ancestry, while lower-than-expected rates were obtained for congenital dislocation of the hip, and for babies with multiple congenital anomalies patterns, both of them attributed to underascertainment of minor defects. These observations do not support the suspicion of an elevated birth prevalence rate for anencephaly, neural tube defects, or any other major congenital malformation in Cubatão.