[Descriptive epidemiologic study of congenital abnormalities of the central nervous system in Spain (1976-1982)].

Authors present an epidemiologic study of the five most frequent congenital birth defects of the central nervous system: anencephaly, spina bifida, encephalocele, hydrocephaly and microcephaly. Over a total of 409 liveborns with some of these anomalies, gathered from 1976 to 1982 in 46 maternities spread all over Spanish geography, they analyze its prevalence at birth, temporary and geographical distribution, sex ratio, gestational age, birth weight and maternal age. To analyze some of these variables they have separated different types of anomalies in three groups depending if they were present as an only defect (isolated), together with other defects in a not syndromic picture (associated), and forming part of a described syndrome (syndromes). This separation is an intention of forming homogeneous ethiopathogenic groups upon which epidemiologic methodology can be applied with assurance to interpret results in a right way.