Background and aims The incidence of cerebral palsy in preterm children is correlated to gestational age, and has been reported to decrease. The objective of this study is to analyse the incidence and risk factors for CP, as well as the subtype and severity of CP over a 22 year period.

Methods Retrospective analysis of a cohort of very preterm infants born between 1990 and 2011, with 1996 infants hospitalised in our level III NICU, and a decrease in mortality from 25 to 8%. Follow-up was offered to the 1717 (86%) survivors. Cerebral palsy was diagnosed at the 18 months visit and was confirmed at a later appointment. In the first years children were evaluated with the Griffiths Mental Development Scales, and with the Bayley Scales, 2nd edition later on. Severity was assessed with cognitive as well as sensorial function, and with the Gross Motor Function Classification system.

Results 1626 children were evaluated, 74 presented with cerebral palsy (4.5%), among them 32% with spastic quadriplegic, 39% spastic diplegic, 26% spastic hemiplegic and 1% ataxic subtypes. The rate of CP, the mean gestational age (28 weeks, SD 13 days) and birthweight (1162 SD 382 g) of the children with CP did not change across the years. Preliminary results show a change of subtype and diminishing severity of CP across the years.

Conclusions Despite improvements in neonatal care and increased survival, CP incidence has not changed over a period of 22 years, but its quality and severity have changed.