School-age outcomes in children who were extremely low birth weight from four international population-based cohorts

Objective. The aim of this study was to determine whether learning and school problems in extremely low birth weight (ELBW) and reference children differ between cohorts in different countries. Methods. Participants were 4 international population-based cohorts of ELBW survivors who were 500 to 1000 g birth weight from New Jersey, central-west Ontario, Bavaria, and Holland (n = 532) and were followed longitudinally from birth. Psychometric data were collected independently and prospectively and included at least 1 measure of cognitive status and 1 measure of achievement administered to the children between the ages of 8 and 11 years. Adjustments were made for comparison of all measures based on reference norms within each country. Information on special educational assistance and grade repetition was obtained from the parents. Results. The overall follow-up rate was 84% ( range: 74% - 90%; n = 436). The proportion of children who performed within the normal range (greater than or equal to 85) were as follows: IQ between 44% and 62%; reading between 46% and 81%; arithmetic between 31% and 76%; and spelling between 39% and 65%. Children from New Jersey had the lowest rates of cognitive and achievement deficits, and Bavarian children did less well in achievement scores relative to their peers and other cohorts. Despite these differences, more than half of all cohorts required special educational assistance and/or repeated a grade. Conclusions. School difficulties were found to be a serious sequelae of ELBW in all 4 countries, an observation that has social and economic implications.