A comparative analysis of birthweight for gestational age standards

The possible consequences of the use of various birthweight-for-gestational age standards in a local population were investigated. Birthweight-for-gestational age standards based on the analysis of 55 387 births occurring to women resident in the area of the Greater Glasgow Health Board (GGHB) between 1975 and 1979 were estimated. The Glasgow based standard was then compared with a number of growth standards reported for other populations, including the widely adopted standards of Thomson et al. (1968). The relative performance of each standard when applied to the Glasgow population was assessed by calculating the sensitivity, specificity and predictive value of the various standards vis-à-vis the distribution of light-for-dates infants defined according to the Glasgow standard. The results suggest that both the accurate assessment of fetal growth at birth and the evaluation of screening procedures for antenatal detection of growth retardation require growth standards reflecting the pattern of fetal growth and development in the population at risk.