Developmental outcome at 18 and 24 months of age in very preterm children: a cohort study from 1996 to 1997

Objective: To determine the effect of prematurity (gestational age (GA) < 32 weeks) on developmental outcome at the corrected age of 18 and 24 months in a regionally defined, prospective cohort study. Study design: The Leiden Follow-Up Project on Prematurity (LFUPP) includes all liveborn infants < 32 weeks GA, born in 1996/1997 in three Dutch health regions (n = 266). Mental and psychomotor developmental indices (MDI, PDI) were determined with the Bayley Scales of Infant Development I: greater than or equal to - 1 S.D.: normal, - 2 to - 1 S.D.: moderate delay and < - 2 S.D.: severe delay. Results: At 18 months 168 (71%) and at 24 months, 151 children (64%) of 235 survivors were assessed. Moderate to severely delayed mental and/or psychomotor development occurred in 40% of the children at both ages. Children lost to follow-up were of lower socioeconomic status and more frequently of non-Dutch origin. Since non-Dutch origin negatively affected the outcome at both test ages, availability of the data of these children would probably have worsened the outcome. Postnatal treatment with dexamethasone was associated with an increased risk of delayed development. Other independent predictors of delayed development were bronchopulmonary dysplasia at 18 months and ethnicity, maternal age at birth, birthweight and gender at 24 months. After adjustment for these other predictors of delayed development, the mean PDI of dexamethasone-treated infants was 16.1 points lower than of non-treated infants at 18 months (p = 0.03) and 12.7 points lower at 24 months (p = 0.04). Conclusions: At 18 and 24 months corrected age, 40% of the very prematurely born children had both delayed mental and/or psychomotor development. Treatment with dexamethasone postnatally was a major risk factor for delayed (psychomotor) development. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.