456 Change in Cerebral Palsy Incidence and Severity Among Children Born Preterm in 1990-2005: A Hospital-Based Cohort Study

Background: Cerebral palsy (CP) is a neurodevelopmental condition that can be wellrecognized from early childhood onward.Aims: To examine CP incidence, severity and associated factors among 2960 preterm survivors of a level III neonatal intensive care unit, born 1990- 2005.Methods: Inclusion criteria: gestational age < 34wks and admission < 4 days after birth. Sixteen potentially relevant factors were analyzed. The cohort was divided in period I: 1990-1993 n=661; II: 1994-1997 n=726; III: 1998-2001 n=723 and IV: 2002-2005 n=850. The Gross Motor Function Classification System (GMFCS) was used to evaluate the severity of CP at a mean age of 32.9 (SD 5.3) months. Logistic regression analyses were used.Results: CP incidence decreased from 6.5% in period I, to 2.6%, 2.9% and 2.2% in period II-IV (p<.001). Simultaneously, cystic periventricular leukomalacia (c-PVL) decreased from 3.3% in period I to 1.7%, 1.0% and 1.3% in period II-IV (p=.004); especially c-PVL grade III from 2.3% in period I to 1.0%, 1.1% and 0.2% in period II-IV (p=.003). The number of children classified in GMFCS Levels III-V in period I compared to IV also decreased (p=.035). Independent risk factors for CP: c-PVL (Odds Ratio (OR): 92.7; 95% CI: 46.1-186.4) and severe intraventricular haemorrhage (OR: 12.8; 95% CI: 7.5-22.0). Independent protective factors: antenatal antibiotics (OR: 0.6; 95% CI: 0.3-1.0) and presence of an arterial line (OR: 0.4; 95% CI: 0.3-0.8).Conclusions: CP incidence and severity declined from 1990-1993 onward in preterm born children and this could especially be attributed to a reduction in severe c-PVL.