Outcome among surviving very low birthweight infants: a meta-analysis. Because published outcome studies are the only available source of data about the morbidity among surviving very low birthweight infants (VLBW, less than 1500 g) a search was carried out of 1136 references in the English language. A total of 111 outcome studies were found that reported morbidity data in cohorts of VLBW infants born since 1960. The methods used and results obtained in these studies were systematically assessed. No agreement exists about the definition of study populations, descriptive statistics, or measurement of outcome. Follow up ranged from six months to 14 years. In 85 cohorts the incidence of cerebral palsy was recorded, and in 106 that of disability. Studies that followed up infants for longer time periods reported higher incidences of disability. Studies from the United States reported higher incidences of disability than those from other countries. The median incidence of cerebral palsy among all the cohorts studied was 7.7%, and the median incidence of disability was 25.0%. Despite substantial improvements in the mortality of VLBW infants, poor outcomes among survivors are common. 