Congenital malformations of the central nervous system in a 1-year birth cohort followed to the age of 14 years.

A 1-year birth cohort from northern Finland comprised 12,058 children, 96% of all live-born infants born in the region in 1966. The development and morbidity of these children were followed up to the age of 14 years. Altogether, 40 children (25 boys and 15 girls) 3.32 per 1,000 suffered from congenital malformations of the central nervous system (CNS). Fourteen (1.16) had spina bifida cystica, 17 (1.41) hydrocephalus, and 9 (0.75) miscellaneous other malformations. Altogether, 14 children died during the follow-up period, giving a prevalence of 2.21 per 1,000 at 14 years. Additional neurological handicaps, mental retardation, cerebral palsy or epilepsy were present in 23 children, 13 of whom had multiple handicaps. Of these children 26% were able to attend an ordinary school in the class appropriate for their age. It is concluded that the incidences for CNS malformations obtained in this study are very much higher than those reported in the Finnish Register of Congenital Malformations, but correspond very well to the figures obtained in the British 1958 birth cohort, which was studied in an analogous way.