Infantile hydrocephalus: declining prevalence in preterm infants.

The prevalence and aetiological panorama of infantile hydrocephalus in western Sweden have been followed since the late 1960s. A significant increase in the live birth prevalence of very preterm infants with infantile hydrocephalus was found, from 6.99 per 1000 in the birth year period 1973-78 to 25.37 in 1983-86, and owing to an increased survival of very preterm infants with a high risk of hydrocephalus, secondary to an intraventricular haemorrhage occurring in the perinatal period. In the present study covering the birth years 1991-94, a declining prevalence to 13.69 per 1000 very preterm infants was found. In moderately preterm and term groups, mostly with prenatal aetiologies, the prevalence was unchanged. Outcome in surviving children with infantile hydrocephalus remained essentially the same as in previous studies, indicating that the underlying aetiology is the most decisive factor with respect to ensuing neuroimpairments.